Bismuth mediated barbier synthesis of <i>α</i>-homoallylic alcohols via a sigmatropic rearrangement in [bmim][HSO<sub>4</sub>]
作者:Sucheta Chatterjee、Papiya Dey、Seema V. Kanojia、Subrata Chattopadhyay、Dibakar Goswami
DOI:10.1080/00397911.2020.1854785
日期:2021.3.4
A novel protocol for the Bismuth metal mediated regioselctive crotylation of aldehydes yielding α-homoallylic alcohols has been developed using 20 mol% [bmim][HSO4] as a metal activator, as well as...
The reaction of crotyltrialkylstannanes (1) with aldehydes in the presence of BF3,OEt2, produces the corresponding erythro homoallyl alcohols (2) predominantly regardless of the geometry of the double bond. Further, the Lewis acid mediated reaction exhibits the enhanced Cram selectivity in comparison with other allylic organometallic reactions which proceed in the absence of Lewis acids. Use of AlCl3-i-PrOH
The reaction of but-2-enyltributylstannane with certain aldehydes in the presence of AlCl3–PriOH produces the α-adduct (3) either predominantly or exclusively, while the reaction in the presence of ordinary Lewis acids, such as TiCl4, SnCl4, and BF3·OEt2, affords the γ-adduct (2) exclusively.