TiCl<sub>4</sub>-Promoted Multicomponent Reaction: A New Entry to Functionalized α-Amino Acids
作者:Arun K. Ghosh、Chun-Xiao Xu、Sarang S. Kulkarni、Donald Wink
DOI:10.1021/ol048302j
日期:2005.1.1
TiCl4-promoted multicomponent reactions involving N-tosyl imino ester, cyclic enol ether, and silane reagents in a single one-pot operation provide functionalized alpha-amino acids with multiple stereogenic centers in good to excellent yields. Cis/trans selectivities with optically active substituted dihydrofurans have been investigated.
Asymmetric multicomponent reactions: convenient access to acyclic stereocenters and functionalized cyclopentenoids
作者:Arun K. Ghosh、Sarang S. Kulkarni、Chun-Xiao Xu、Khriesto Shurrush
DOI:10.1016/j.tetasy.2008.04.005
日期:2008.5
Asymmetric multicomponent reactions of optically active phenyl dihydrofuran, keto ester or N-tosyl imino ester, and allylsilane provided functionalized phenyl tetrahydrofurans with multiple stereogenic centers diastereoselectively. Cleavage of the resulting substituted tetrahydrofurans readily provided acyclic derivatives with three contiguous asymmetric centers via an acyloxycarbenium ion intermediate. Ring closing olefin metathesis, using Grubbs catalyst, afforded functionalized cyclopentene derivatives in optically active form. A one-pot tandem tetrahydrofuran ring cleavage followed by ring closing olefin metathesis also provided functionalized cyclopentenes in good yield. (C) 2008 Elsevier Ltd. All rights reserved.
Asymmetric Multicomponent Reactions: Diastereoselective Synthesis of Substituted Pyrrolidines and Prolines
作者:Arun K. Ghosh、Sarang Kulkarni、Chun-Xiao Xu、Phillip E. Fanwick
DOI:10.1021/ol061672i
日期:2006.9.1
A novel diastereoselective synthesis of substitutedpyrrolidines has been developed. Asymmetric multicomponentreactions of optically active phenyldihydrofuran, N-tosyl imino ester, and silane reagents in a one-pot operation afforded highlysubstitutedpyrrolidine derivatives diastereoselectively. The reaction is quite efficient and constructed up to three stereogenic centers in a single operation