Conjugate addition reactions of chiral (E)-crotylsilanes: application to an asymmetric [3 + 2] cyclopentane annulation
摘要:
Functionalized (E)-crotylsilanes 1 undergo Lewis acid promoted conjugate addition reactions with alpha-substituted enals and methyl vinyl ketone 2 to produce tetrasubstituted cyclopentanes 3 with high levels of diastereoselection. The reaction is believed to proceed by an initial 1,4-addition which is followed by a 1,2-silyl migration and a final cyclization step involving the derived boron enolate resulting in the construction of the cyclopentanoid product.
Asymmetric Synthesis of Homoallylic Amines and Functionalized Pyrrolidines via Direct Amino-Crotylation of In Situ Generated Imines
作者:Jennifer V Schaus、Nareshkumar Jain、James S Panek
DOI:10.1016/s0040-4020(00)00870-x
日期:2000.12
The asymmetric synthesis of functionalized homoallylic amines and silyl functionalizedpyrrolidines through the Lewis acid promoted condensation of chiral (E)-crotylsilanes with sulfonyl imines and in situ generated N-acyl imines is described. We had anticipated that this bond construction could be used in the asymmetric synthesis of the N-terminal amino acid subunit of the nikkomycins. Aryl sulfonyl
Panek, James S.; Yang, Michael, Journal of the American Chemical Society, 1991, vol. 113, # 17, p. 6594 - 6600
作者:Panek, James S.、Yang, Michael
DOI:——
日期:——
Remote asymmetric induction in diastereoface selective addition reactions of optically active .alpha.-substituted-.beta.-silyl (E)-hexenoates with achiral .alpha.-alkoxy and .beta.-alkoxy acetals
作者:James S. Panek、Michael Yang
DOI:10.1021/jo00020a009
日期:1991.9
Optically active and diastereomerically pure (E)-crotylsilanes 1 function as effective chiral carbon nucleophiles in trimethylsilyl trifluoromethanesulfonate (TMSOTf) catalyzed asymmetric addition reactions of achiral, alpha-alkoxy and beta-alkoxy acetals 2, resulting in the highly diastereo- and enantioselective construction of homoallylic ethers with excellent levels of 1,4- and 1,5-asymmetric induction.
Direct Amino-Crotylsilylation of Achiral Acetals and Aldehydes: Asymmetric Synthesis of Homoallylic Amines and Functionalized Pyrrolidines
作者:James S. Panek、Nareshkumar F. Jain
DOI:10.1021/jo00089a004
日期:1994.5
The condensation between chiral (E)-crotyl-silanes 1 and in situ-generated achiral N-acylimines produces homoallylic N-acylamines 3 or tetrasubstituted N-acylpyrrolidines 4 with high levels of diastereoselection.
Conjugate addition reactions of chiral (E)-crotylsilanes: application to an asymmetric [3 + 2] cyclopentane annulation
作者:James S. Panek、Nareshkumar F. Jain
DOI:10.1021/jo00061a001
日期:1993.4
Functionalized (E)-crotylsilanes 1 undergo Lewis acid promoted conjugate addition reactions with alpha-substituted enals and methyl vinyl ketone 2 to produce tetrasubstituted cyclopentanes 3 with high levels of diastereoselection. The reaction is believed to proceed by an initial 1,4-addition which is followed by a 1,2-silyl migration and a final cyclization step involving the derived boron enolate resulting in the construction of the cyclopentanoid product.