N-Heterocycliccarbenes (NHCs) catalyzing aza-Claisen rearrangement of α,β-unsaturated enals with cyclic vinylogous amides under oxidative conditions generating potentially biologically active dihydropyridinone-fused uracils have been developed. This strategy represents a unique NHC-activation-based path with the use of 6-aminouracils as stable α,β-diEWG cyclic vinylogous amides for the efficient synthesis
efficient synthesis of aldehydes from acidchlorides with hydrosilanes as a reducing agent in the presence of a palladium catalyst has been achieved. A simple mixture of commercially available Pd(dba)2 and Mes3P as a catalyst realized the reduction of various acidchlorides including aliphatic acidchlorides and α,β-unsaturated acidchlorides to the corresponding aldehydes in good to high yields under
Enantioselective Organocatalytic Reactions of 4-Hydroxycoumarin and 4-Hydroxypyrone with α,β-Unsaturated Aldehydes - An Efficient Michael Addition-Acetalization Cascade to Chromenones, Quinolinones and Pyranones
作者:Magnus Rueping、Estíbaliz Merino、Erli Sugiono
DOI:10.1002/adsc.200800340
日期:2008.9.5
An efficient, organocatalyticenantioselective addition-cyclization reaction of cyclic 1,3-dicarbonyl compounds with different α,β-unsaturatedaldehydes has been developed. The diarylprolinol ether-catalyzed reactioncascade provides a variety of chromenones, quinolinones and pyranones in good yields and with excellent enantioselectivities.