Strategic use of oxophilic (hard) gold(III) and π-philic (soft) gold(I) catalysts provides access to two types of cyclic ethers from propargylic alcohols. Thus, heating propargylic alcohols with an oxophilic gold(III) catalyst (AuBr3) results in cyclization to afford cyclic ethers bearing an acetylenic moiety, due to coordination of gold(III) to the oxygen of the propargylic hydroxyl group. On the
Platinum-Catalyzed Synthesis of β-Keto Tetrahydropyrans and Cyclic Dienolethers
作者:Qiren Liang、Mingxing Qian、Mina Razzak、Jef K. De Brabander
DOI:10.1002/asia.201100113
日期:2011.8.1
Depending on the presence of a suitably placed alcohol group proximal or distal to the propargylic center, a cyclo‐reorganization occurs that delivers either valuable β‐keto tetrahydropyrans (from propargylic alcohols), or cyclicdienolethers (from propargylic esters).