Gold-Catalyzed Oxidative Ring Expansions and Ring Cleavages of Alkynylcyclopropanes by Intermolecular Reactions Oxidized by Diphenylsulfoxide
作者:Chia-Wen Li、Kamalkishore Pati、Guan-You Lin、Shariar Md. Abu Sohel、Hsiao-Hua Hung、Rai-Shung Liu
DOI:10.1002/anie.201004647
日期:2010.12.17
A golden opportunity: A novel gold‐catalyzed oxidative ring‐expansion of unactivated cyclopropylalkynes using Ph2SO has been developed (see scheme). For substrates bearing a donor group at the cyclopropane ring, preliminary results reveal a distinct cleavage of the cyclopropane unit; such a ring cleavage is further applicable to the synthesis of 2H‐pyrans. L=P(tBu)2(o‐biphenyl), Tf=triflate.
千载难逢的机会:已开发出一种新的使用Ph 2 SO的未活化环丙基炔烃的金催化氧化环扩环反应(参见方案)。对于在环丙烷环上带有供体基团的底物,初步结果表明,环丙烷单元具有明显的裂解。这样的开环进一步适用于2 H-吡喃的合成。L = P(t Bu)2(邻联苯),Tf =三氟甲磺酸。