The Experts below are selected from a list of 207 Experts worldwide ranked by ideXlab platform
Toshiro Harada - One of the best experts on this subject based on the ideXlab platform.
-
asymmetric desymmetrization of 2 substituted 1 3 propanediols via catalytic enantioselective Ring Cleavage reaction of cyclic acetal derivatives
Synlett, 2005Co-Authors: Toshiro Harada, Koudai ShiraishiAbstract:Non-enzymatic desymmetrization of 2-substituted 1,3propanediols leading to the enantiomerically enriched 3-benzyloxy-1-propanols was achieved by using oxazaborolidinone-catalyzed enantioselective Ring-Cleavage reaction ofthe cyclic acetal derivatives with dimethylsilyl ketene S,O-acetal as a key reaction.
-
Asymmetric Desymmetrization of 2-Substituted 1,3-Propanediols by Using Oxazaborolidinone-Mediated Enantioselective Ring-Cleavage of Prochiral Acetal Derivatives
Synlett, 2002Co-Authors: Toshiro Harada, Keiko ImaiAbstract:Nonenzymatic desymmetrization of 2-substituted 1,3-propanediols leading to the enantiomerically enriched 3-benzyloxy-1-propanols was achieved by using oxazaborolidinone-mediated enantioselective Ring-Cleavage reaction of the dioxane acetal derivatives.
-
Deracemization ofanti-1,2-diols leading totrans-epoxides via oxazaborolidine-mediated enantiomer-differentiating Ring-Cleavage of acetal derivatives
Tetrahedron Letters, 1999Co-Authors: Toshiro Harada, Tomohito Nakamura, Motoharu KinugasaAbstract:Abstract An enantioconvergent transformation of racemic anti -1,2-diols to enantiomerically enriched (71–96% ee) trans -epoxides is realized via chiral oxazaborolidine-mediated enantiomer-differentiating Ring-Cleavage reaction of the acetal derivatives.
-
Desymmetrization of meso-1,3-tetrols via oxazaborolidine-mediated enantiotopic group selective Ring-Cleavage of bisacetal derivatives
Tetrahedron Letters, 1998Co-Authors: Toshiro Harada, Takayuki Egusa, Akira OkuAbstract:Meso-1,3,5,7-heptanetetrol and -1,3,6,8-octanetetrol were desymmetrized via enantiotopic group selective Ring-Cleavage reaction of their bisacetal derivatives using a chiral oxazaborolidine.
-
Kinetic resolution of cyclic acetals derived from 1,3-alkanediols via oxazaborolidine-mediated enantioselective Ring-Cleavage reaction
Tetrahedron Letters, 1998Co-Authors: Toshiro Harada, Takayuki Egusa, Motoharu Kinugasa, Akira OkuAbstract:Abstract Racemic acetals derived from 1,3-alkanediols undergo kinetic resolution with a selectivity factor s = 5.2–14 in Ring-Cleavage reaction with methallyldimethylphenylsilane mediated by a N -mesylphenylalanine derived oxazaborolidine.
Marc Lemaire - One of the best experts on this subject based on the ideXlab platform.
-
TMDS as a Dual‐Purpose Reductant in the Regioselective Ring Cleavage of Hexopyranosyl Acetals to Ethers
European Journal of Organic Chemistry, 2012Co-Authors: Yin-jie Zhang, Wissam Dayoub, Guorong Chen, Marc LemaireAbstract:1,1,3,3-Tetramethyldisiloxane (TMDS) has been developed as an excellent dual-purpose reductant for the highly regioselective Ring Cleavage of various hexopyranosyl 4,6-O-acetals with Cu(OTf)2 or AlCl3 to afford the corresponding primary and secondary ethers. Its application to the concise synthesis of carbohydrate-based surfactants is highlighted.
-
TMDS as a dual-purpose reductant in the regioselective Ring Cleavage of hexopyranosyl acetals to ethers.
European Journal of Organic Chemistry, 2012Co-Authors: Yin-jie Zhang, Wissam Dayoub, Guorong Chen, Marc LemaireAbstract:1,1,3,3-Tetramethyldisiloxane (TMDS) has been developed as an excellent dual-purpose reductant for the highly regioselective Ring Cleavage of various hexopyranosyl 4,6-O-acetals with Cu(OTf)2 or AlCl3 to afford the corresponding primary and secondary ethers. Its application to the concise synthesis of carbohydrate-based surfactants is highlighted.
Akira Oku - One of the best experts on this subject based on the ideXlab platform.
-
Desymmetrization of meso-1,3-tetrols via oxazaborolidine-mediated enantiotopic group selective Ring-Cleavage of bisacetal derivatives
Tetrahedron Letters, 1998Co-Authors: Toshiro Harada, Takayuki Egusa, Akira OkuAbstract:Meso-1,3,5,7-heptanetetrol and -1,3,6,8-octanetetrol were desymmetrized via enantiotopic group selective Ring-Cleavage reaction of their bisacetal derivatives using a chiral oxazaborolidine.
-
Kinetic resolution of cyclic acetals derived from 1,3-alkanediols via oxazaborolidine-mediated enantioselective Ring-Cleavage reaction
Tetrahedron Letters, 1998Co-Authors: Toshiro Harada, Takayuki Egusa, Motoharu Kinugasa, Akira OkuAbstract:Abstract Racemic acetals derived from 1,3-alkanediols undergo kinetic resolution with a selectivity factor s = 5.2–14 in Ring-Cleavage reaction with methallyldimethylphenylsilane mediated by a N -mesylphenylalanine derived oxazaborolidine.
-
Asymmetric Synthesis of Functionalized Secondary Alcohols by Catalytic Ring-Cleavage Reactions of Cyclic Acetals Derived from (R)-1, 3-Butanediol
Bulletin of the Chemical Society of Japan, 1996Co-Authors: Motoharu Kinugasa, Toshiro Harada, Takayuki Egusa, Katsuhiro Fujita, Akira OkuAbstract:In the presence of a catalytic amount (0.1—0.2 molar amount) of a 2-phenyl-1,3,2-oxazaborolidin-5-one, prepared by the reaction of dichlorophenylborane and N-(trifluoromethylsulfonyl)-L-phenylalanine, and enol silyl ethers ((R2)2C=C(R3)OTMS; R3 = t-BuS, EtS, EtO, Ph) (1.1-1.5 molar amount), chiral cyclic acetals 6 derived from (R)-1,3-butanediol and aldehydes undergo an efficient Ring-Cleavage reaction with the inversion of the stereochemistry at the acetal carbon to give the anti isomer of the corresponding products with high stereoselectivity. The reaction is applicable to acetals derived from aromatic, aliphatic, and α,β-unsaturated aldehydes. Not only enol silyl ethers, but also methallyltrimethylsilane and allyltributyltin, can be employed as nucleophiles, leading to the selective formation of the anti isomer of the corresponding allylated Ring-Cleavage products. Removal of the chiral auxiliary from these Ring-Cleavage products by a two-step sequence ((i) PCC (ii) Bn2NH2(CF3CO2)) furnishes enantiomer...
Keiko Imai - One of the best experts on this subject based on the ideXlab platform.
-
Asymmetric Desymmetrization of 2-Substituted 1,3-Propanediols by Using Oxazaborolidinone-Mediated Enantioselective Ring-Cleavage of Prochiral Acetal Derivatives
Synlett, 2002Co-Authors: Toshiro Harada, Keiko ImaiAbstract:Nonenzymatic desymmetrization of 2-substituted 1,3-propanediols leading to the enantiomerically enriched 3-benzyloxy-1-propanols was achieved by using oxazaborolidinone-mediated enantioselective Ring-Cleavage reaction of the dioxane acetal derivatives.
Yin-jie Zhang - One of the best experts on this subject based on the ideXlab platform.
-
TMDS as a Dual‐Purpose Reductant in the Regioselective Ring Cleavage of Hexopyranosyl Acetals to Ethers
European Journal of Organic Chemistry, 2012Co-Authors: Yin-jie Zhang, Wissam Dayoub, Guorong Chen, Marc LemaireAbstract:1,1,3,3-Tetramethyldisiloxane (TMDS) has been developed as an excellent dual-purpose reductant for the highly regioselective Ring Cleavage of various hexopyranosyl 4,6-O-acetals with Cu(OTf)2 or AlCl3 to afford the corresponding primary and secondary ethers. Its application to the concise synthesis of carbohydrate-based surfactants is highlighted.
-
TMDS as a dual-purpose reductant in the regioselective Ring Cleavage of hexopyranosyl acetals to ethers.
European Journal of Organic Chemistry, 2012Co-Authors: Yin-jie Zhang, Wissam Dayoub, Guorong Chen, Marc LemaireAbstract:1,1,3,3-Tetramethyldisiloxane (TMDS) has been developed as an excellent dual-purpose reductant for the highly regioselective Ring Cleavage of various hexopyranosyl 4,6-O-acetals with Cu(OTf)2 or AlCl3 to afford the corresponding primary and secondary ethers. Its application to the concise synthesis of carbohydrate-based surfactants is highlighted.
