Unexpected Skeletal Rearrangement in the Gold(I)/Silver(I)-Catalyzed Conversion of 7-Aryl-1,6-enynes to Bicyclo[3.2.0]hept-6-enes via Hidden Brønsted Acid Catalysis

Published

Journal Article

© 2017 American Chemical Society. Cycloaddition of an isotopically labeled 7-phenyl-1,6-enyne catalyzed by a mixture of LAuCl [L = P(t-Bu)2o-biphenyl)] and AgSbF6 forms the corresponding 6-phenylbicyclo[3.2.0]hept-6-ene with concomitant scrambling of the olefinic CPh (C6) and CH (C7) groups of the product. The extent of C6/C7 scrambling was sensitive to the nature of the silver salt and was likewise observed in the cycloaddition of the 7-phenyl-1,6-enyne catalyzed by mixtures of [LAuNCMe]+SbF6- and Brønsted acids such as HOTf. These observations and low-temperature NMR analysis of organic and organometallic intermediates in the cycloaddition process were in accord with a mechanism for C6/C7 scrambling initiated by protonation of free bicyclo[3.2.0]hept-7-ene to generate a bicyclo[3.2.0]heptyl cation that undergoes reversible alkyl migration, presumably involving bicyclo[4.1.0]- and bicyclo[3.1.1]heptyl cations prior to elimination of the C7 proton.

Full Text

Duke Authors

Cited Authors

  • Kim, N; Brooner, REM; Widenhoefer, RA

Published Date

  • February 13, 2017

Published In

Volume / Issue

  • 36 / 3

Start / End Page

  • 673 - 678

Electronic International Standard Serial Number (EISSN)

  • 1520-6041

International Standard Serial Number (ISSN)

  • 0276-7333

Digital Object Identifier (DOI)

  • 10.1021/acs.organomet.6b00868

Citation Source

  • Scopus