Diastereoselectivity in the osmium tetraoxide promoted dihydroxylation of chiral (E)-crotylsilane: asymmetric synthesis of silyl-functionalized .gamma.-lactones
摘要:
The catalytic osmylation of enantiomerically enriched (E)-crotylsilanes (2S,3R)-1 and (2R,3R)-2 containing a homoallylic, nitrogen-bearing stereocenter proceeds with good to high levels of diastereoselection generating silyl-functionalized trans-4,5 substituted gamma-lactones 3 and 5 as the major diastereomers.
Highly regio- and diastereoselective synthesis of bis-triazolines
作者:Yu Chen、James S. Panek
DOI:10.1016/j.tet.2021.132119
日期:2021.5
A highly efficient homodimerization of chiral α-azido-α,β-unsaturated esters was achieved by a 1,3-dipolar cycloaddition on series of (E)-methyl 4-azido-6-methoxy-5-methyl-6-phenylhex-2-enoates. Both 4,5-syn and 4,5-anti allylic azides could be used effectively to access the dimer by this method.