Diastereoselective Allylstannane Additions to (<i>S</i>)-5,6-Dihydro-2<i>H</i>-5-phenyloxazin-2-one. A Concise Synthesis of (<i>S</i>)-β-Methylisoleucine
作者:Julie A. Pigza、Tadeusz F. Molinski
DOI:10.1021/ol1001126
日期:2010.3.19
The addition of allyl stannanes to (S)-4,5-dihydro-5-phenyl-2H-oxazinone (3) was achieved under Bronsted acid catalysis to give 2-allylmorpholinones with high diastereoselectivity (up to dr 14.2:1). The product of dimethylallyltributylstannane addition to 3 was converted to L-beta-methylisoleucine, an alpha-amino acid residue found in the complex, biologically active marine-derived peptides polytheonamides A and B, and polydiscamides A-C.
A Stereoselective aza-Prins Reaction: Rapid Access to Enantiopure Piperidines and Pipecolic Acids
作者:Ramana Reddy Mittapalli、Simon J. Coles、Wim T. Klooster、Adrian P. Dobbs
DOI:10.1021/acs.joc.0c01897
日期:2021.2.5
aza-Prins reaction is a widely employed and highly efficient method for the preparation of saturated nitrogen-containing heterocycles. Its major drawback has always been a lack of diastereoselectivity and the formation of racemic products. Herein, we address these problems and report, for the first time, the synthesis of both diastereomerically and enantiopure multiply substituted piperidines via the aza-Prins