title: Gold-catalyzed carboalkoxylations of 2-ethynylbenzyl ethers to form 1- and 3-substituted 2-methoxy-1-H-indenes: Brønsted acids versus gold catalysis.
abstract: Selective synthesis of 1- and 3-substituted 2-methoxyindenes from the carboalkoxylations of 2-ethynylbenzyl ethers is described; the former is obtained efficiently with P(t-Bu)2(o-biphenyl)AuCl/NaBARF in DCM/MS 4 Å whereas the latter is produced preferably with P(t-Bu)2(o-biphenyl)AuCl/AgNTf2 in pre-dried DCM. Both 1- and 3-substituted 2-indenyl ethers are subjected to ozone oxidations to afford two distinct carbonyl products. Our new data indicate that 1-substituted 2-indenyl ethers are generated from gold catalysts whereas their 3-substituted analogues arise from Brønsted acids.
authors.affiliation: Department of Chemistry, National Tsing-Hua University, Hsinchu, Taiwan, Republic of China. rsliu@mx.nthu.edu.tw.
authors.forename: Chun-Hao
authors.initials: CH
authors.lastname: Chen
authors.forename: Chiou-Dong
authors.initials: CD
authors.lastname: Wang
authors.forename: Yi-Feng
authors.initials: YF
authors.lastname: Hsieh
authors.forename: Rai-Shung
authors.initials: RS
authors.lastname: Liu