An in situ formed palladium hydride catalyst enables the sequential dual isomerization of propargylamide derivatives to 1-amido-1,3-dienes with high chemo- and regioselectivity. The reaction shows ample functional group tolerance, delivering a valuable class of products, including highly deuterated ones, from readily available reagents. The reaction occurs through a complex mechanism studied by DFT
Gold(I)-Catalyzed Enantioselective Ring Expansion of Allenylcyclopropanols
作者:Florian Kleinbeck、F. Dean Toste
DOI:10.1021/ja904055z
日期:2009.7.8
The asymmetric gold(I)-catalyzedring expansion of 1-allenylcyclopropanols is described. The method provides synthetically valuable cyclobutanones with a vinyl-substituted quaternary stereogenic center in high enantioselectivities and yields. The method shows a broad substrate scope, tolerating protected alcohols and amines, alkenes, unsaturated esters, and acetals. The reaction is easily adjustable
Diastereoselective Synthesis of Substituted 2-Phenyltetrahydropyrans as Useful Precursors of Aryl C-Glycosides via Selenoetherification
作者:Michelangelo Gruttadauria、Carmela Aprile、Paolo Lo Meo、Serena Riela、Renato Noto
DOI:10.3987/com-03-9959
日期:——
The cyclization of several substituted 5-phenyl-pent-4-en-l-ols with selenium electrophiles along some mechanistic considerations is discussed. In particular, an efficient diastereoselective synthesis of a 2,3,5,6-tetrasubstitued tetrahydropyran is reported. These findings open an interesting approach: the use of chiral selenium electrophiles for cyclization of chiral substrates. The cyclized products are useful starting material for the synthesis of D- or L-aryl C-glycosides.
Preparation of a <i>cis</i>-Isoprostane Synthon
作者:Douglass F. Taber、John H. Green、Wei Zhang、Renhua Song