title: The skeletal rearrangement of gold- and platinum-catalyzed cycloisomerization of cis-4,6-dien-1-yn-3-ols: pinacol rearrangement and formation of bicyclo[4.1.0]heptenone and reorganized styrene derivatives.
abstract: With gold and platinum catalysts, cis-4,6-dien-1-yn-3-ols undergo cycloisomerizations that enable structural reorganization of cyclized products chemoselectively. The AuCl3-catalyzed cyclizations of 6-substituted cis-4,6-dien-1-yn-3-ols proceeded via a 6-exo-dig pathway to give allyl cations, which subsequently undergo a pinacol rearrangement to produce reorganized cyclopentenyl aldehyde products. Using chiral alcohol substrates, such cyclizations proceed with reasonable chirality transfer. In the PtCl2-catalyzed cyclization of 7,7-disubstituted cis-4,6-dien-1-yn-3-ols, we obtained exclusively either bicyclo[4.1.0]heptenones or reorganized styrene products with varied substrate structures. On the basis of the chemoselectivity/structure relationship, we propose that bicyclo[4.1.0]heptenone products result from 6-endo-dig cyclization, whereas reorganized styrene products are derived from the 5-exo-dig pathway. This proposed mechanism is supported by theoretic calculations.
authors.affiliation: Department of Chemistry, National Tsing-Hua University, Hsinchu, Taiwan, ROC.
authors.forename: Jhih-Meng
authors.initials: JM
authors.lastname: Tang
authors.forename: Sabyasachi
authors.initials: S
authors.lastname: Bhunia
authors.forename: Shariar Md
authors.initials: SM
authors.lastname: Abu Sohel
authors.forename: Ming-Yuan
authors.initials: MY
authors.lastname: Lin
authors.forename: Hsin-Yi
authors.initials: HY
authors.lastname: Liao
authors.forename: Swarup
authors.initials: S
authors.lastname: Datta
authors.forename: Arindam
authors.initials: A
authors.lastname: Das
authors.forename: Rai-Shung
authors.initials: RS
authors.lastname: Liu