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
Intramolecular iodoetherification of ene or diene ketals: facile synthesis of spiroketals
作者:Hiromichi Fujioka、Kenji Nakahara、Hideki Hirose、Kie Hirano、Tomohiro Oki、Yasuyuki Kita
DOI:10.1039/c0cc03933k
日期:——
A novel and rapid approach to chiral mono- or di-substituted spiroketals based on remote asymmetric induction by intramolecular iodoetherification of ene or diene ketals has been developed. This strategy concisely offers 5,5- and 5,6-spiroketals including the natural insect pheromone of the wasp.