The Experts below are selected from a list of 1578 Experts worldwide ranked by ideXlab platform
Takayuki Doi - One of the best experts on this subject based on the ideXlab platform.
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Scalable Solution-Phase Synthesis of the Biologically Active Cyclodepsipeptide Destruxin E, a Potent Negative Regulator of Osteoclast Morphology
2014Co-Authors: Masahito Yoshida, Hiroshi Sato, Yoshitaka Ishida, Hiroshi Nakagawa, Takayuki DoiAbstract:The scalable solution-phase synthesis of the cyclodepsipeptide destruxin E (1) has been achieved. Diastereoselective dihydroxylation of the terminal alkene in a 2-alkoxy-4-pentenoic amide, 7, was successfully accomplished utilizing (DHQD)2PHAL as the chiral ligand, and it was found that the use of the l-proline moiety in the substrate as a chiral auxiliary was essential for the induction of high diastereoselectivity to afford the key compound 4 on a gram scale. MNBA-mediated Macrolactonization of 3 was also performed without formation of the dimerized product even under higher-dilution conditions, and it is noteworthy that the internal hydrogen bonds and s-cis configuration of the amide bond between N-methylalanine and N-methylvaline in the cyclization precursor 3 would assist in the Macrolactonization to provide the macrolactone 2 without forming a dimerized product. Finally, epoxide formation in the side chain afforded destruxin E (1) on a gram scale in high purity (>98%)
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Scalable Solution-Phase Synthesis of the Biologically Active Cyclodepsipeptide Destruxin E, a Potent Negative Regulator of Osteoclast Morphology
The Journal of organic chemistry, 2013Co-Authors: Masahito Yoshida, Hiroshi Sato, Yoshitaka Ishida, Hiroshi Nakagawa, Takayuki DoiAbstract:The scalable solution-phase synthesis of the cyclodepsipeptide destruxin E (1) has been achieved. Diastereoselective dihydroxylation of the terminal alkene in a 2-alkoxy-4-pentenoic amide, 7, was successfully accomplished utilizing (DHQD)2PHAL as the chiral ligand, and it was found that the use of the l-proline moiety in the substrate as a chiral auxiliary was essential for the induction of high diastereoselectivity to afford the key compound 4 on a gram scale. MNBA-mediated Macrolactonization of 3 was also performed without formation of the dimerized product even under higher-dilution conditions, and it is noteworthy that the internal hydrogen bonds and s-cis configuration of the amide bond between N-methylalanine and N-methylvaline in the cyclization precursor 3 would assist in the Macrolactonization to provide the macrolactone 2 without forming a dimerized product. Finally, epoxide formation in the side chain afforded destruxin E (1) on a gram scale in high purity (>98%).
Wen-wen Zhang - One of the best experts on this subject based on the ideXlab platform.
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Macrolactonization of Alkynyl Alcohol through Rh(I)/Yb(III) Catalysis.
Organic letters, 2018Co-Authors: Wen-wen Zhang, Tao-tao GaoAbstract:A catalytic Macrolactonization through oxidative cyclization of alkynyl alcohol by synergistic transition-metal and Lewis-acid catalysis was developed. Because the alkynyl alcohol substrates involved in this method are different from the seco acids that are used in conventional Macrolactonization methods, the current method provides a strategically distinct entry to macrolactones. In addition to the operational simplicity, this Macrolactonization protocol proceeds at relatively high concentration, precluding the need for high dilution or slow addition procedures.
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Macrolactonization of alkynyl alcohol through rh i yb iii catalysis
Organic Letters, 2018Co-Authors: Wen-wen Zhang, Tao-tao GaoAbstract:A catalytic Macrolactonization through oxidative cyclization of alkynyl alcohol by synergistic transition-metal and Lewis-acid catalysis was developed. Because the alkynyl alcohol substrates involved in this method are different from the seco acids that are used in conventional Macrolactonization methods, the current method provides a strategically distinct entry to macrolactones. In addition to the operational simplicity, this Macrolactonization protocol proceeds at relatively high concentration, precluding the need for high dilution or slow addition procedures.
Tao-tao Gao - One of the best experts on this subject based on the ideXlab platform.
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Macrolactonization of Alkynyl Alcohol through Rh(I)/Yb(III) Catalysis.
Organic letters, 2018Co-Authors: Wen-wen Zhang, Tao-tao GaoAbstract:A catalytic Macrolactonization through oxidative cyclization of alkynyl alcohol by synergistic transition-metal and Lewis-acid catalysis was developed. Because the alkynyl alcohol substrates involved in this method are different from the seco acids that are used in conventional Macrolactonization methods, the current method provides a strategically distinct entry to macrolactones. In addition to the operational simplicity, this Macrolactonization protocol proceeds at relatively high concentration, precluding the need for high dilution or slow addition procedures.
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Macrolactonization of alkynyl alcohol through rh i yb iii catalysis
Organic Letters, 2018Co-Authors: Wen-wen Zhang, Tao-tao GaoAbstract:A catalytic Macrolactonization through oxidative cyclization of alkynyl alcohol by synergistic transition-metal and Lewis-acid catalysis was developed. Because the alkynyl alcohol substrates involved in this method are different from the seco acids that are used in conventional Macrolactonization methods, the current method provides a strategically distinct entry to macrolactones. In addition to the operational simplicity, this Macrolactonization protocol proceeds at relatively high concentration, precluding the need for high dilution or slow addition procedures.
Gowravaram Sabitha - One of the best experts on this subject based on the ideXlab platform.
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Synthetic Studies toward the Revised Aglycone of Mandelalide A
ChemistrySelect, 2017Co-Authors: Praveen Ankireddy, Sandeep Ankireddy, Gowravaram SabithaAbstract:Synthesis of a silyl derivative of revised aglycone of marine anticancer macrolide Mandelalide A is described. The synthetic highlights include acid catalyzed epoxide opening, Chelation- controlled Grignard reaction, Still-Gennari olefination, Pd-catalyzed intramolecular alkoxycarbonylation, Kocien′ski-Julia olefination and Shiina Macrolactonization as keysteps.
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First total synthesis of Pestalotioprolide C and its C7 epimer
Tetrahedron Letters, 2017Co-Authors: K. Siva Nagi Reddy, Gowravaram SabithaAbstract:Abstract The first total synthesis of Pestalotioprolide C and C7- epi -Pestalotioprolide C adopting Noyori asymmetric reduction, HWE Olefination and Shiina Macrolactonization as the key steps has been described.
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Total Synthesis of Antifungal Macrolide Sch 725674
ChemistrySelect, 2016Co-Authors: Yugendar Reddy, Gowravaram SabithaAbstract:Total synthesis of the 14-membered macrolide Sch 725674 has been developed that is based on macrocyclic ring closure either by Yamaguchi or Shiina Macrolactonization and the construction of the precursor seco acid by Pd(OH)2 transformation of primary propargyl alcohol/HWE olefination between two fragments is shown.
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Synthetic studies toward pondaplin: total synthesis of pondaplin analogues ☆
Tetrahedron Letters, 2005Co-Authors: Gowravaram Sabitha, R. Swapna, R. Satheesh Babu, Jhillu S. YadavAbstract:Syntheses of synthetic analogues of pondaplin 1 have been achieved. Final macrolide construction was accomplished using a Keck Macrolactonization reaction.
Tushar Kanti Chakraborty - One of the best experts on this subject based on the ideXlab platform.
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Studies directed towards the synthesis of botcinolides: synthesis of the nonalactone ring of 2-epibotcinolide☆
Tetrahedron Letters, 2006Co-Authors: Tushar Kanti Chakraborty, Rajib Kumar GoswamiAbstract:Synthesis of the polyoxygenated nonalactone ring of 2-epibotcinolide was achieved using a highly stereoselective aldol reaction of the titanium enolate from a lactate-derived chiral ketone, a stereoselective dihydroxylation and a Yamaguchi Macrolactonization reaction.
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studies directed towards the synthesis of stevastelins a Macrolactonization approach to stevastelin b
Tetrahedron Letters, 2001Co-Authors: Tushar Kanti Chakraborty, Subhash Chandra Ghosh, Shantanu DuttaAbstract:A synthetic approach towards the cyclic depsipeptide immunosuppressant stevastelin B, based on the stereoselective synthesis of its propionate-derived fatty acid segment 6 that was coupled with the tripeptide 7 leading to the advanced stage acyclic intermediate 5, is described. In spite of our best efforts, the crucial Macrolactonization reaction was not successful.
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Studies directed towards the synthesis of stevastelins—a Macrolactonization approach to stevastelin B
Tetrahedron Letters, 2001Co-Authors: Tushar Kanti Chakraborty, Subhash Chandra Ghosh, Shantanu DuttaAbstract:A synthetic approach towards the cyclic depsipeptide immunosuppressant stevastelin B, based on the stereoselective synthesis of its propionate-derived fatty acid segment 6 that was coupled with the tripeptide 7 leading to the advanced stage acyclic intermediate 5, is described. In spite of our best efforts, the crucial Macrolactonization reaction was not successful.
