Monosubstituted γ-lactols 1a−1c, 3a−3c and 4a−4c, as well as disubstituted γ-lactol 5 and the γ-hydroxy-substituted γ-lactone 6, were transformed into disubstituted tetrahydrofuran derivatives by treatment with allyl- and propargylsilanes in the presence of Lewis acids. The diastereoselectivities were moderate to excellent and are interpreted by application of the Felkin−Anh model to cyclic oxocarbenium
Direct Organocatalytic Multicomponent Synthesis of Enantiopure <i>γ</i>
-Butyrolactones via Tandem Knoevenagel-Michael-Lactonization Sequence
作者:Tushar M. Khopade、Amol D. Sonawane、Jyotsna S. Arora、Ramakrishna G. Bhat
DOI:10.1002/adsc.201701084
日期:2017.11.23
An expedient and straightforward protocol is developed for the synthesis of highly enantiopure synthesis of γ-butyrolactones. For the first time, one pot enantioselective organocatalytic multicomponent reaction (OMCR) is explored to construct functionalized butyrolactones without the use of pre-functionalized substrates and expensive transition metals. The protocol is proved to be reproducible on a