(2-Bromoethyl)sulfonium Trifluoromethanesulfonates in Stereoselective Annulation Reactions for the Formation of Fused Bicyclic Epoxides and Aziridines
作者:Sven P. Fritz、Zulfiquar Ali、Matthew G. Unthank、Eoghan M. McGarrigle、Varinder K. Aggarwal
DOI:10.1002/hlca.201200455
日期:2012.12
A versatile and simple method is reported for the synthesis of bicyclic epoxide and aziridinefused heterocycles (up to 98% yield, up to 96 : 4 er or up to 15 : 1 dr), using a tandem Michaeladdition/JohnsonCoreyChaykovsky annulation approach. A new chiral (2‐bromoethyl)sulfonium reagent is described, based on an easily available chiral sulfide; it promotes or enhances stereoselectivity in the reaction
Epoxy-Annulations by Reactions of α-Amido Ketones with Vinyl Sulfonium Salts. Reagent versus Substrate Control and Kinetic Resolution
作者:Matthew G. Unthank、Bahareh Tavassoli、Varinder K. Aggarwal
DOI:10.1021/ol800318h
日期:2008.4.1
Diphenyl vinyl sulfonium salt and chiral amido-ketones undergo highlydiastereoselective epoxy-annulation reactions in good yield. The use of a chiral vinyl sulfonium salt dominates the stereochemical outcome of the annulation reaction (reagent control is greater than substrate control), and this has allowed the kinetic resolution of racemic amido-ketones to be achieved.