Homoallylic sterol/indium(III) Lewis acid: a novel enantioselective allylation system exhibiting α-regioselectivity
作者:Teck-Peng Loh、Qi-Ying Hu、Yew-Keong Chok、Kui-Thong Tan
DOI:10.1016/s0040-4039(01)02011-1
日期:2001.12
A homoallylic sterol/indium(III) Lewis acid reagent system Was Utilized for the enantioselective and a-regioselective allylation of various aldehydes. (C) 2001 Elsevier Science Ltd. All rights reserved.
Stereocontrolled Synthesis of Linear 22<i>R</i>-Homoallylic Sterols via a Triflic Acid-Catalyzed 2-Oxonia Cope Rearrangement
作者:Teck-Peng Loh、Qi-Ying Hu、Li-Ting Ma
DOI:10.1021/ol026136e
日期:2002.7.1
[reaction: see text] Poor stereoselectivity caused by the involvement of side reaction pathways was observed in the In(OTf)(3)-catalyzed allyl-transfer reaction (R = electron-withdrawing group). Subsequently, it was found that the employment of triflic acid (TFA) as catalyst could successfully suppress the side reaction pathways and, hence, achieve high stereoselectivity.
A new mechanistic proposal for the origin of α-homoallylic alcohols in indium-mediated allylation reactions in water
作者:Teck-Peng Loh、Kui-Thong Tan、Qi-Ying Hu
DOI:10.1016/s0040-4039(01)01884-6
日期:2001.12
A new mechanism is proposed for the α-regioselective indium-mediated allylation reaction in water. Based on the results and observations obtained from an NMR study, a cross-over experiment and the complete inversion of the stereochemistry of 22β γ-adduct homoallylic sterols to the 22α α-adduct homoallylic sterols, it is suggested that the initially formed γ-adduct undergoes a bond cleavage to generate