The Silylalkyne-Prins Cyclization: Stereoselective Synthesis of Tetra- and Pentasubstituted Halodihydropyrans
作者:Pedro O. Miranda、Miguel A. Ramírez、Víctor S. Martín、Juan I. Padrón
DOI:10.1021/ol060247m
日期:2006.4.1
[reaction: see text] A new type of Prins cyclization using silylated secondary homopropargylic alcohols and aldehydes yielding tetra- and pentasubstituted dihydropyrans is described. The presence of the trimethylsilyl group in the triple bond favors the Prins cyclization and minimizes the 2-oxonia-[3,3]-sigmatropic rearrangement as a competitive alternative pathway. Ab initio theoretical calculations
Chiral Brønsted acid catalyzed enantioselective allenylation of aldehydes
作者:Leleti Rajender Reddy
DOI:10.1039/c2cc34371a
日期:——
A versatile and highly enantioselective chiral Brønsted acid-catalyzed allenylation of aldehydes with propargyl borolane is reported. The reaction is shown to be practical and quite general with a broad substrate scope covering aryl, heteroaryl, α,β-unsaturated, and aliphatic aldehydes.