title: The mechanism and regioselectivity of gold(I) or platinum(II) catalyzed intramolecular hydroarylation to pyrrolopyridinones and pyrroloazepinones.
abstract: We report here the theoretical analysis of the mechanism and regioselectivity of gold(I) or platinum(II) catalyzed intramolecular hydroarylation to pyrrolopyridinones and pyrroloazepinones. AuPH3(+) and PtCl2 have been considered to account for some experimental observations. Our calculation results indicate that in the case of cationic gold the nucleophilic attack of the pyrrole on the activated alkyne occurs in an exo-dig fashion generating a six-membered intermediate, which upon deprotonation and protodeauration forms pyrrolopyridinone. When platinum is used, an endo-dig fashion is observed generating a seven-membered intermediate. After deprotonation and protodeplatination pyrroloazepinone is formed. Whether for exo-dig (gold(I)) or endo-dig (platinum(II)) cyclization, a [1,2]-migration would not be needed.
authors.affiliation: Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization of Gansu Province and College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, P. R. China. fangr@lzu.edu.cn yanglz@lzu.edu.cn.
authors.forename: Ran
authors.initials: R
authors.lastname: Fang
authors.forename: Xiaoxiao
authors.initials: X
authors.lastname: Wei
authors.forename: Lizi
authors.initials: L
authors.lastname: Yang