Tin-free radical/ionic hydroxymethylation of secondary and tertiary alkyliodides proceeded efficiently in the presence of tetrabutylammonium borohydride as the hydrogen source under atmospheric pressure of CO in conjunction with photoirradiation using black light. Two possible mechanisms were proposed, both of which involve hybrid radical/ionicprocesses.
X=Y–ZH Systems as potential 1,3-dipoles. Part 52: Fused-ring forming electrophile induced oxime→nitrone→cycloaddition cascades
作者:H Ali Dondas、Ronald Grigg、Sylvie Thibault
DOI:10.1016/s0040-4020(01)00661-5
日期:2001.8
Electrophileinducedcyclisation of oximes onto endocyclic alkenes and exo-methylene cycloalkanes occurs stereo- and regio-specifically generating cis-fused bicyclic nitrones in good yield. Subsequent facially selective cycloaddition with N-methylmaleimide occurs in good yield. The sequence may be carried out as a one-pot procedure and results in the formation of 4 bonds, 2 rings and 6 stereocentres
Stereoselective electrophile-induced mono- and bis-cyclisation–fragmentation reactions of alkenyl oxime O-allyl and O-benzyl ethers. Synthesis of dihydropinidine
作者:H Ali Dondas、Ronald Grigg、Jasothara Markandu、Trevor Perrior、Tekka Suzuki、Sylvie Thibault、W Anthony Thomas、Mark Thornton-Pett
DOI:10.1016/s0040-4020(01)01118-8
日期:2002.1
Phenylseleny bromide-induced cyclisation of γ- and δ-unsaturated aldoxime and ketoxime O-allyl and O-benzyl ethers is followed by a slow fragmentation of the resultant oxyiminium ions furnishing cyclic iminium salts which are readily reduced to pyrrolidines, piperidines or tetrahydroisoquinolines by sodium borohydride; dialkenyl oximes yield indolizidines and quinolizidines by an analogous sequence