palladium-catalyzed cross-coupling of o-allylic and o-vinylic phenols with vinylic halides and triflates produces substituted dihydrobenzopyrans and dihydrobenzofurans respectively in good to high yields. The proposed mechanism involves vinylpalladium addition to the olefin, rearrangement to a π-allylpalladium intermediate and subsequent intramolecular nucleophilic displacement of palladium.
Palladium-catalyzed cross-coupling of unsaturated phenols with vinylic halides and triflates
作者:Richard C. Larock、Hoseok Yang、Paola Pace、Sandro Cacchi、Giancarlo Fabrizi
DOI:10.1016/s0040-4039(97)10502-0
日期:1998.1
The palladium-catalyzed cross-coupling of o-vinylic phenols with vinylic halides and triflates produces substituted dihydrobenzopyrans and dihydrobenzofurans respectively in good to high yields.
The synthesis of both mono and bisbenzannulated spiroketals using an oxidative radical cyclization approach is investigated. Although unsuccessful in uncovering a novel route toward bisbenzannulated spiroketals, the oxidative radical cyclization does facilitate a new approach to monobenzannulated spiroketals such as those found in berkelic acid and in the chaetoquadrins.
Brønsted Acid Catalyzed Intramolecular Allylic Substitution Reaction of Allylic Alcohols: A Facile Synthesis of 2-Vinylchromans
作者:Chang-Hua Ding、Bin Xu、Yun-Fan Li、Yu-Ting Xi、Kai-Ji Hu、Qitao Tan
DOI:10.1055/a-2301-9223
日期:——
Brønsted acidcatalyzedintramolecular allylic substitution reaction of secondary and tertiary allylic alcohols has been developed. A variety of 2-vinylchromans were efficiently prepared in moderate to excellent yields. The given method features wide substrate scope, operational simplicity, and mild, metal-free reaction conditions. The practicability of the method was demonstrated by a gram-scale reaction