Generation of chiral N-acylpyridinium ions by means of silyl triflates and their diastereoselective trapping reactions: formation of N-acyldihydropyridines and N-acyldihydropyridones
作者:Cornelia E Hoesl、Markus Maurus、Jörg Pabel、Kurt Polborn、Klaus Th Wanner
DOI:10.1016/s0040-4020(02)00675-0
日期:2002.8
An efficient method for the generation of chiral N-acylpyridinium salts from various pyridines and a chiral acid chloride promoted by means of silyltriflates as additives is presented. The stereoselectiveaddition of organometallic reagents to the intermediate chiral N-acylpyridinium ions led to α-substituted N-acyldihydropyridines and N-acyldihydropyridones in good yields, whereas no or minor amounts
Aza Diels–Alder reactions of sulfinimines with the Rawal diene
作者:Robert Kawęcki
DOI:10.1016/j.tetasy.2006.04.026
日期:2006.5
The azaDiels–Alderreaction of optically active sulfinimines with the Rawal diene leads to enantiomerically enriched dihydropyridones with ees up to 90%. The reaction was catalyzed by TMSOTf. The best results were obtained using 10-isobornylsulfinimines. Removal of the sulfinyl auxiliary occurred during workup of the reaction mixture. The reaction most likely proceeds via a stepwise mechanism. The