Role of Pseudoephedrine as Chiral Auxiliary in the “Acetate-Type” Aldol Reaction with Chiral Aldehydes; Asymmetric Synthesis of Highly Functionalized Chiral Building Blocks
作者:Marta Ocejo、Luisa Carrillo、Jose L. Vicario、Dolores Badía、Efraim Reyes
DOI:10.1021/jo101878j
日期:2011.1.21
have studied in depth the aldol reaction between acetamide enolates and chiral α-heterosubstituted aldehydes using pseudoephedrine as chiralauxiliary under double stereodifferentiation conditions, showing that high diastereoselectivities can only be achieved under the matched combination of reagents and provided that the α-heteroatom-containing substituent of the chiral aldehyde is conveniently protected
Hydrogenation of pyrrolizin-3-ones; new routes to pyrrolizidines
作者:Xavier L. M. Despinoy、Hamish McNab
DOI:10.1039/b910199c
日期:——
catalysts. Good diastereoselectivity (up to >97:3, depending on catalysts and solvent) can be achieved if the pyrrolizin-3-one is substituted at the 1- (or 7-) position(s), but the selectivity is reduced if both positions are substituted. Subsequent deoxygenation of the pyrrolizidin-3-ones provides concise, diastereoselectiveroutes to the necine bases (±)-heliotridane 5, (±)-isoretronecanol 6 and (±)retronecanol