THE SYNTHESIS AND REACTIONS OF DIVINYL CARBONIUM IONS
作者:T. S. Sorensen
DOI:10.1139/v64-410
日期:1964.12.1
A number of alkyl-substituted trienes have been protonated. In some cases, the existence of divinyl carboniumions can be shown, while in others, a cyclization reaction leading to, cyclopentenyl carboniumions takes place so rapidly that the presumed initially formed divinyl carbonium is never observed. Steric arguments are invoked to explain these differences. Complete n.m.r. and ultraviolet spectral
Enantioselective oxa‐Diels–Alder Sequences of Dendralenes
作者:Yi‐Min Fan、Li‐Juan Yu、Michael G. Gardiner、Michelle L. Coote、Michael S. Sherburn
DOI:10.1002/anie.202204872
日期:2022.9.26
A highly enantioselective synthesis of target-relevant oxabicyclic systems is reported. The synthesis involves a sequence of two formal oxa-Diels–Alder reactions between a wide variety of achiral dendralenes and a carbonyl dienophile, proceeding with the generation of two new rings, four new covalent bonds and up to four new stereocenters.