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Shunichi Hashimoto - One of the best experts on this subject based on the ideXlab platform.
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asymmetric total synthesis of englerin a through catalytic diastereo and enantioselective Carbonyl Ylide cycloaddition
Chemistry: A European Journal, 2015Co-Authors: Taiki Hanari, Masahiro Anada, Naoyuki Shimada, Hisanori Nambu, Yasunobu Kurosaki, N Thrimurtulu, Shunichi HashimotoAbstract:An asymmetric total synthesis of the guaiane sesquiterpene (−)-englerin A, a potent and selective inhibitor of the growth of renal cancer cell lines, was accomplished. The basis of the approach is a highly diastereo- and enantioselective Carbonyl Ylide cycloaddition with an ethyl vinyl ether dipolarophile under catalysis by dirhodium(II) tetrakis[N-tetrachlorophthaloyl-(S)-tert-leucinate], [Rh2(S-TCPTTL)4], to construct the oxabicyclo[3.2.1]octane framework with concomitant introduction of the oxygen substituent at C9 on the exo-face. Another notable feature of the synthesis is ruthenium tetraoxide-catalyzed chemoselective oxidative conversion of C9 ethyl ether to C9 acetate.
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catalytic asymmetric synthesis of descurainin via 1 3 dipolar cycloaddition of a Carbonyl Ylide using rh2 r tcpttl 4
Tetrahedron Letters, 2010Co-Authors: Naoyuki Shimada, Masahiro Anada, Hisanori Nambu, Taiki Hanari, Yasunobu Kurosaki, Shunichi HashimotoAbstract:Abstract A catalytic asymmetric synthesis of descurainin has been achieved by incorporating an enantioselective 1,3-dipolar cycloaddition, a stereoselective alkene hydrogenation, an oxidation with Fremy’s salt and a regioselective demethylation with NbCl5 as the key step. The 1,3-dipolar cycloaddition of a Carbonyl Ylide derived from tert-butyl 2-diazo-5-formyl-3-oxopetanoate with 4-hydroxy-3-methoxyphenylacetylene in the presence of dirhodium(II) tetrakis[N-tetrachlorophthaloyl-(R)-tert-leucinate], Rh2(R-TCPTTL)4, provided an 8-oxabicyclo[3.2.1]octane skeleton in 95% ee.
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catalytic asymmetric synthesis of the endo 6 aryl 8 oxabicyclo 3 2 1 oct 3 en 2 one natural product from ligusticum chuanxing via 1 3 dipolar cycloaddition of a formyl derived Carbonyl Ylide using rh2 s tcpttl 4
Journal of Organic Chemistry, 2010Co-Authors: Naoyuki Shimada, Masahiro Anada, Motoo Shiro, Hisanori Nambu, Taiki Hanari, Yasunobu Kurosaki, Koji Takeda, Shunichi HashimotoAbstract:The reaction of a six-membered cyclic formyl-Carbonyl Ylide derived from α-diazo-β-ketoester with phenylacetylene derivatives under the catalysis of dirhodium(II) tetrakis[N-tetrachlorophthaloyl-(S)-tert-leucinate], Rh2(S-TCPTTL)4, provides cycloadducts containing an 8-oxabicyclo[3.2.1]octane ring system in up to 97% ee. This represents the first example of an enantioselective 1,3-dipolar cycloaddition of a cyclic formyl-Carbonyl Ylide. Using this catalytic process, an asymmetric synthesis of endo-6-aryl-8-oxabicyclo[3.2.1]oct-3-en-2-one natural product 1 from Ligusticum chuanxing Hort. has been achieved.
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catalytic asymmetric synthesis of the endo 6 aryl 8 oxabicyclo 3 2 1 oct 3 en 2 one natural product from ligusticum chuanxing via 1 3 dipolar cycloaddition of a formyl derived Carbonyl Ylide using rh2 s tcpttl 4
Journal of Organic Chemistry, 2010Co-Authors: Naoyuki Shimada, Masahiro Anada, Motoo Shiro, Hisanori Nambu, Taiki Hanari, Yasunobu Kurosaki, Koji Takeda, Shunichi HashimotoAbstract:The reaction of a six-membered cyclic formyl-Carbonyl Ylide derived from α-diazo-β-ketoester with phenylacetylene derivatives under the catalysis of dirhodium(II) tetrakis[N-tetrachlorophthaloyl-(S...
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catalytic asymmetric construction of the exo 7 aryl 6 8 dioxabicyclo 3 2 1 octane framework of psoracorylifols b and c using a Carbonyl Ylide cycloaddition strategy
Bulletin of The Korean Chemical Society, 2010Co-Authors: Yasunobu Kurosaki, Masahiro Anada, Naoyuki Shimada, Hisanori Nambu, Shunichi HashimotoAbstract:Conse-quently, the development of an enantioselective version of this sequence catalyzed by chiral dirhodium(II) complexes has be-come a challenging objective. In this process, the chiral dirho-dium(II) catalyst must be capable of associating with Carbonyl Ylide intermediates in the cycloaddition step,
David M Hodgson - One of the best experts on this subject based on the ideXlab platform.
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Correction to Synthesis of (−)-6,7-Dideoxysqualestatin H5 by Carbonyl Ylide Cycloaddition–Rearrangement and Cross-electrophile Coupling
2018Co-Authors: Younes Fegheh-hassanpour, Tanzeel Arif, Herman O. Sintim, Hamad Al H. Mamari, David M HodgsonAbstract:Correction to Synthesis of (−)-6,7-Dideoxysqualestatin H5 by Carbonyl Ylide Cycloaddition–Rearrangement and Cross-electrophile Couplin
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synthesis of 6 7 dideoxysqualestatin h5 by Carbonyl Ylide cycloaddition rearrangement and cross electrophile coupling
Organic Letters, 2017Co-Authors: Younes Feghehhassanpour, Herman O. Sintim, Tanzeel Arif, Hamad Al H. Mamari, David M HodgsonAbstract:An asymmetric synthesis of (−)-6,7-dideoxysqualestatin H5 is reported. Key features of the synthesis include the following: (1) highly diastereoselective n-alkylation of a tartrate acetonide enolate and subsequent oxidation–hydrolysis to provide an asymmetric entry to a β-hydroxy-α-ketoester motif; (2) facilitation of Rh(II)-catalyzed cyclic Carbonyl Ylide formation–cycloaddition by co-generation of keto and diazo functionality through ozonolysis of an unsaturated hydrazone; and (3) stereoretentive Ni-catalyzed Csp3–Csp2 cross-electrophile coupling between tricarboxylate core and unsaturated side chain to complete the natural product.
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Synthesis of (−)-6,7-Dideoxysqualestatin H5 by Carbonyl Ylide Cycloaddition–Rearrangement and Cross-electrophile Coupling
2017Co-Authors: Younes Fegheh-hassanpour, Tanzeel Arif, Herman O. Sintim, Hamad Al H. Mamari, David M HodgsonAbstract:An asymmetric synthesis of (−)-6,7-dideoxysqualestatin H5 is reported. Key features of the synthesis include the following: (1) highly diastereoselective n-alkylation of a tartrate acetonide enolate and subsequent oxidation–hydrolysis to provide an asymmetric entry to a β-hydroxy-α-ketoester motif; (2) facilitation of Rh(II)-catalyzed cyclic Carbonyl Ylide formation–cycloaddition by co-generation of keto and diazo functionality through ozonolysis of an unsaturated hydrazone; and (3) stereoretentive Ni-catalyzed Csp3–Csp2 cross-electrophile coupling between tricarboxylate core and unsaturated side chain to complete the natural product
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Synthetic and computational studies on the tricarboxylate core of 6,7-dideoxysqualestatin H5 involving a Carbonyl Ylide cycloaddition-rearrangement
Organic & biomolecular chemistry, 2010Co-Authors: David M Hodgson, Carol Villalonga-barber, Jonathan M. Goodman, Silvina C. PellegrinetAbstract:Reaction of diazodiketoesters 17 and 28 with methyl glyoxylate in the presence of catalytic rhodium(II) acetate generates predominantly the 6,8-dioxabicyclo[3.2.1]octanes 29 and 30, respectively. Acid-catalysed rearrangement of the corresponding alcohol 31 favours, at equilibrium, the 2,8-dioxabicyclo[3.2.1]octane skeleton 33 of the squalestatins–zaragozic acids. Force field calculations on the position of the equilibrium gave misleading results. DFT calculations were correct in suggesting that the energy difference between 31 and 33 should be small, but did not always suggest the right major product. Calculation of the NMR spectra of the similar structures could be used to assign the isomers with a high level of confidence.
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catalytic enantioselective tandem Carbonyl Ylide formation intramolecular cycloaddition with unsaturated α diazo β e diketo sulfones
Tetrahedron-asymmetry, 2009Co-Authors: David M Hodgson, Rebecca Glen, Alison Judith RedgraveAbstract:The synthesis and 1,3-dipolar cycloaddition reactions of unsaturated α-diazo-β,e-diketo sulfones 7 using chiral rhodium catalysts (up to 71.5:28.5 er) are described.
Naoyuki Shimada - One of the best experts on this subject based on the ideXlab platform.
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asymmetric total synthesis of englerin a through catalytic diastereo and enantioselective Carbonyl Ylide cycloaddition
Chemistry: A European Journal, 2015Co-Authors: Taiki Hanari, Masahiro Anada, Naoyuki Shimada, Hisanori Nambu, Yasunobu Kurosaki, N Thrimurtulu, Shunichi HashimotoAbstract:An asymmetric total synthesis of the guaiane sesquiterpene (−)-englerin A, a potent and selective inhibitor of the growth of renal cancer cell lines, was accomplished. The basis of the approach is a highly diastereo- and enantioselective Carbonyl Ylide cycloaddition with an ethyl vinyl ether dipolarophile under catalysis by dirhodium(II) tetrakis[N-tetrachlorophthaloyl-(S)-tert-leucinate], [Rh2(S-TCPTTL)4], to construct the oxabicyclo[3.2.1]octane framework with concomitant introduction of the oxygen substituent at C9 on the exo-face. Another notable feature of the synthesis is ruthenium tetraoxide-catalyzed chemoselective oxidative conversion of C9 ethyl ether to C9 acetate.
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catalytic asymmetric synthesis of descurainin via 1 3 dipolar cycloaddition of a Carbonyl Ylide using rh2 r tcpttl 4
Tetrahedron Letters, 2010Co-Authors: Naoyuki Shimada, Masahiro Anada, Hisanori Nambu, Taiki Hanari, Yasunobu Kurosaki, Shunichi HashimotoAbstract:Abstract A catalytic asymmetric synthesis of descurainin has been achieved by incorporating an enantioselective 1,3-dipolar cycloaddition, a stereoselective alkene hydrogenation, an oxidation with Fremy’s salt and a regioselective demethylation with NbCl5 as the key step. The 1,3-dipolar cycloaddition of a Carbonyl Ylide derived from tert-butyl 2-diazo-5-formyl-3-oxopetanoate with 4-hydroxy-3-methoxyphenylacetylene in the presence of dirhodium(II) tetrakis[N-tetrachlorophthaloyl-(R)-tert-leucinate], Rh2(R-TCPTTL)4, provided an 8-oxabicyclo[3.2.1]octane skeleton in 95% ee.
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catalytic asymmetric synthesis of the endo 6 aryl 8 oxabicyclo 3 2 1 oct 3 en 2 one natural product from ligusticum chuanxing via 1 3 dipolar cycloaddition of a formyl derived Carbonyl Ylide using rh2 s tcpttl 4
Journal of Organic Chemistry, 2010Co-Authors: Naoyuki Shimada, Masahiro Anada, Motoo Shiro, Hisanori Nambu, Taiki Hanari, Yasunobu Kurosaki, Koji Takeda, Shunichi HashimotoAbstract:The reaction of a six-membered cyclic formyl-Carbonyl Ylide derived from α-diazo-β-ketoester with phenylacetylene derivatives under the catalysis of dirhodium(II) tetrakis[N-tetrachlorophthaloyl-(S)-tert-leucinate], Rh2(S-TCPTTL)4, provides cycloadducts containing an 8-oxabicyclo[3.2.1]octane ring system in up to 97% ee. This represents the first example of an enantioselective 1,3-dipolar cycloaddition of a cyclic formyl-Carbonyl Ylide. Using this catalytic process, an asymmetric synthesis of endo-6-aryl-8-oxabicyclo[3.2.1]oct-3-en-2-one natural product 1 from Ligusticum chuanxing Hort. has been achieved.
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catalytic asymmetric synthesis of the endo 6 aryl 8 oxabicyclo 3 2 1 oct 3 en 2 one natural product from ligusticum chuanxing via 1 3 dipolar cycloaddition of a formyl derived Carbonyl Ylide using rh2 s tcpttl 4
Journal of Organic Chemistry, 2010Co-Authors: Naoyuki Shimada, Masahiro Anada, Motoo Shiro, Hisanori Nambu, Taiki Hanari, Yasunobu Kurosaki, Koji Takeda, Shunichi HashimotoAbstract:The reaction of a six-membered cyclic formyl-Carbonyl Ylide derived from α-diazo-β-ketoester with phenylacetylene derivatives under the catalysis of dirhodium(II) tetrakis[N-tetrachlorophthaloyl-(S...
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catalytic asymmetric construction of the exo 7 aryl 6 8 dioxabicyclo 3 2 1 octane framework of psoracorylifols b and c using a Carbonyl Ylide cycloaddition strategy
Bulletin of The Korean Chemical Society, 2010Co-Authors: Yasunobu Kurosaki, Masahiro Anada, Naoyuki Shimada, Hisanori Nambu, Shunichi HashimotoAbstract:Conse-quently, the development of an enantioselective version of this sequence catalyzed by chiral dirhodium(II) complexes has be-come a challenging objective. In this process, the chiral dirho-dium(II) catalyst must be capable of associating with Carbonyl Ylide intermediates in the cycloaddition step,
Hisanori Nambu - One of the best experts on this subject based on the ideXlab platform.
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asymmetric total synthesis of englerin a through catalytic diastereo and enantioselective Carbonyl Ylide cycloaddition
Chemistry: A European Journal, 2015Co-Authors: Taiki Hanari, Masahiro Anada, Naoyuki Shimada, Hisanori Nambu, Yasunobu Kurosaki, N Thrimurtulu, Shunichi HashimotoAbstract:An asymmetric total synthesis of the guaiane sesquiterpene (−)-englerin A, a potent and selective inhibitor of the growth of renal cancer cell lines, was accomplished. The basis of the approach is a highly diastereo- and enantioselective Carbonyl Ylide cycloaddition with an ethyl vinyl ether dipolarophile under catalysis by dirhodium(II) tetrakis[N-tetrachlorophthaloyl-(S)-tert-leucinate], [Rh2(S-TCPTTL)4], to construct the oxabicyclo[3.2.1]octane framework with concomitant introduction of the oxygen substituent at C9 on the exo-face. Another notable feature of the synthesis is ruthenium tetraoxide-catalyzed chemoselective oxidative conversion of C9 ethyl ether to C9 acetate.
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catalytic asymmetric synthesis of descurainin via 1 3 dipolar cycloaddition of a Carbonyl Ylide using rh2 r tcpttl 4
Tetrahedron Letters, 2010Co-Authors: Naoyuki Shimada, Masahiro Anada, Hisanori Nambu, Taiki Hanari, Yasunobu Kurosaki, Shunichi HashimotoAbstract:Abstract A catalytic asymmetric synthesis of descurainin has been achieved by incorporating an enantioselective 1,3-dipolar cycloaddition, a stereoselective alkene hydrogenation, an oxidation with Fremy’s salt and a regioselective demethylation with NbCl5 as the key step. The 1,3-dipolar cycloaddition of a Carbonyl Ylide derived from tert-butyl 2-diazo-5-formyl-3-oxopetanoate with 4-hydroxy-3-methoxyphenylacetylene in the presence of dirhodium(II) tetrakis[N-tetrachlorophthaloyl-(R)-tert-leucinate], Rh2(R-TCPTTL)4, provided an 8-oxabicyclo[3.2.1]octane skeleton in 95% ee.
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catalytic asymmetric synthesis of the endo 6 aryl 8 oxabicyclo 3 2 1 oct 3 en 2 one natural product from ligusticum chuanxing via 1 3 dipolar cycloaddition of a formyl derived Carbonyl Ylide using rh2 s tcpttl 4
Journal of Organic Chemistry, 2010Co-Authors: Naoyuki Shimada, Masahiro Anada, Motoo Shiro, Hisanori Nambu, Taiki Hanari, Yasunobu Kurosaki, Koji Takeda, Shunichi HashimotoAbstract:The reaction of a six-membered cyclic formyl-Carbonyl Ylide derived from α-diazo-β-ketoester with phenylacetylene derivatives under the catalysis of dirhodium(II) tetrakis[N-tetrachlorophthaloyl-(S)-tert-leucinate], Rh2(S-TCPTTL)4, provides cycloadducts containing an 8-oxabicyclo[3.2.1]octane ring system in up to 97% ee. This represents the first example of an enantioselective 1,3-dipolar cycloaddition of a cyclic formyl-Carbonyl Ylide. Using this catalytic process, an asymmetric synthesis of endo-6-aryl-8-oxabicyclo[3.2.1]oct-3-en-2-one natural product 1 from Ligusticum chuanxing Hort. has been achieved.
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catalytic asymmetric synthesis of the endo 6 aryl 8 oxabicyclo 3 2 1 oct 3 en 2 one natural product from ligusticum chuanxing via 1 3 dipolar cycloaddition of a formyl derived Carbonyl Ylide using rh2 s tcpttl 4
Journal of Organic Chemistry, 2010Co-Authors: Naoyuki Shimada, Masahiro Anada, Motoo Shiro, Hisanori Nambu, Taiki Hanari, Yasunobu Kurosaki, Koji Takeda, Shunichi HashimotoAbstract:The reaction of a six-membered cyclic formyl-Carbonyl Ylide derived from α-diazo-β-ketoester with phenylacetylene derivatives under the catalysis of dirhodium(II) tetrakis[N-tetrachlorophthaloyl-(S...
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catalytic asymmetric construction of the exo 7 aryl 6 8 dioxabicyclo 3 2 1 octane framework of psoracorylifols b and c using a Carbonyl Ylide cycloaddition strategy
Bulletin of The Korean Chemical Society, 2010Co-Authors: Yasunobu Kurosaki, Masahiro Anada, Naoyuki Shimada, Hisanori Nambu, Shunichi HashimotoAbstract:Conse-quently, the development of an enantioselective version of this sequence catalyzed by chiral dirhodium(II) complexes has be-come a challenging objective. In this process, the chiral dirho-dium(II) catalyst must be capable of associating with Carbonyl Ylide intermediates in the cycloaddition step,
Masahiro Anada - One of the best experts on this subject based on the ideXlab platform.
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asymmetric total synthesis of englerin a through catalytic diastereo and enantioselective Carbonyl Ylide cycloaddition
Chemistry: A European Journal, 2015Co-Authors: Taiki Hanari, Masahiro Anada, Naoyuki Shimada, Hisanori Nambu, Yasunobu Kurosaki, N Thrimurtulu, Shunichi HashimotoAbstract:An asymmetric total synthesis of the guaiane sesquiterpene (−)-englerin A, a potent and selective inhibitor of the growth of renal cancer cell lines, was accomplished. The basis of the approach is a highly diastereo- and enantioselective Carbonyl Ylide cycloaddition with an ethyl vinyl ether dipolarophile under catalysis by dirhodium(II) tetrakis[N-tetrachlorophthaloyl-(S)-tert-leucinate], [Rh2(S-TCPTTL)4], to construct the oxabicyclo[3.2.1]octane framework with concomitant introduction of the oxygen substituent at C9 on the exo-face. Another notable feature of the synthesis is ruthenium tetraoxide-catalyzed chemoselective oxidative conversion of C9 ethyl ether to C9 acetate.
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catalytic asymmetric synthesis of descurainin via 1 3 dipolar cycloaddition of a Carbonyl Ylide using rh2 r tcpttl 4
Tetrahedron Letters, 2010Co-Authors: Naoyuki Shimada, Masahiro Anada, Hisanori Nambu, Taiki Hanari, Yasunobu Kurosaki, Shunichi HashimotoAbstract:Abstract A catalytic asymmetric synthesis of descurainin has been achieved by incorporating an enantioselective 1,3-dipolar cycloaddition, a stereoselective alkene hydrogenation, an oxidation with Fremy’s salt and a regioselective demethylation with NbCl5 as the key step. The 1,3-dipolar cycloaddition of a Carbonyl Ylide derived from tert-butyl 2-diazo-5-formyl-3-oxopetanoate with 4-hydroxy-3-methoxyphenylacetylene in the presence of dirhodium(II) tetrakis[N-tetrachlorophthaloyl-(R)-tert-leucinate], Rh2(R-TCPTTL)4, provided an 8-oxabicyclo[3.2.1]octane skeleton in 95% ee.
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catalytic asymmetric synthesis of the endo 6 aryl 8 oxabicyclo 3 2 1 oct 3 en 2 one natural product from ligusticum chuanxing via 1 3 dipolar cycloaddition of a formyl derived Carbonyl Ylide using rh2 s tcpttl 4
Journal of Organic Chemistry, 2010Co-Authors: Naoyuki Shimada, Masahiro Anada, Motoo Shiro, Hisanori Nambu, Taiki Hanari, Yasunobu Kurosaki, Koji Takeda, Shunichi HashimotoAbstract:The reaction of a six-membered cyclic formyl-Carbonyl Ylide derived from α-diazo-β-ketoester with phenylacetylene derivatives under the catalysis of dirhodium(II) tetrakis[N-tetrachlorophthaloyl-(S)-tert-leucinate], Rh2(S-TCPTTL)4, provides cycloadducts containing an 8-oxabicyclo[3.2.1]octane ring system in up to 97% ee. This represents the first example of an enantioselective 1,3-dipolar cycloaddition of a cyclic formyl-Carbonyl Ylide. Using this catalytic process, an asymmetric synthesis of endo-6-aryl-8-oxabicyclo[3.2.1]oct-3-en-2-one natural product 1 from Ligusticum chuanxing Hort. has been achieved.
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catalytic asymmetric synthesis of the endo 6 aryl 8 oxabicyclo 3 2 1 oct 3 en 2 one natural product from ligusticum chuanxing via 1 3 dipolar cycloaddition of a formyl derived Carbonyl Ylide using rh2 s tcpttl 4
Journal of Organic Chemistry, 2010Co-Authors: Naoyuki Shimada, Masahiro Anada, Motoo Shiro, Hisanori Nambu, Taiki Hanari, Yasunobu Kurosaki, Koji Takeda, Shunichi HashimotoAbstract:The reaction of a six-membered cyclic formyl-Carbonyl Ylide derived from α-diazo-β-ketoester with phenylacetylene derivatives under the catalysis of dirhodium(II) tetrakis[N-tetrachlorophthaloyl-(S...
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catalytic asymmetric construction of the exo 7 aryl 6 8 dioxabicyclo 3 2 1 octane framework of psoracorylifols b and c using a Carbonyl Ylide cycloaddition strategy
Bulletin of The Korean Chemical Society, 2010Co-Authors: Yasunobu Kurosaki, Masahiro Anada, Naoyuki Shimada, Hisanori Nambu, Shunichi HashimotoAbstract:Conse-quently, the development of an enantioselective version of this sequence catalyzed by chiral dirhodium(II) complexes has be-come a challenging objective. In this process, the chiral dirho-dium(II) catalyst must be capable of associating with Carbonyl Ylide intermediates in the cycloaddition step,