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.
钯催化的邻烯丙基和邻
乙烯基酚与
乙烯基卤化物和
三氟甲磺酸酯的交叉偶联分别以良好或高收率产生了取代的二氢苯并
吡喃和二氢
苯并呋喃。所提出的机理包括
乙烯基钯加到烯烃中,重排成π-烯丙基
钯中间体和随后的分子内亲核置换
钯。