Tris(trimethylsilyl)silane and visible-light irradiation: a new metal- and additive-free photochemical process for the synthesis of indoles and oxindoles
A photochemically promoted intramolecular cyclization of aryl-, vinyl-, and alkyliodo allenes has been developed. The optimal conditions employed [Ir(ppy)2(dtbbpy)]PF6 (1 mol%) as catalyst affording products with high exo selectivity in moderate to good yields. Chiral substrates showed diastereoselectivity of up to 95/5 favoring trans product.
An Approach to Cyclohepta[<i>b</i>]indoles through an Allenamide (4 + 3) Cycloaddition–Grignard Cyclization–Chugaev Elimination Sequence
作者:Shuzhong He、Richard P. Hsung、William R. Presser、Zhi-Xiong Ma、Bryan J. Haugen
DOI:10.1021/ol5006455
日期:2014.4.18
A strategy for synthesizing highly functionalized cyclohepta[b]indoles through a concise (4 + 3) cycloaddition–cyclization–elimination sequence is described. The cycloaddition features nitrogen-stabilized oxyallylcations derived from epoxidations of N-aryl-N-sulfonyl-substituted allenamides, while the cyclization and elimination employed an intramolecular Grignard addition and a one-step Chugaev process
A palladium-catalyzed enantioselective Heck cyclization/dearomatization cascade via capturing the cyclized Heck π-allylpalladium intermediate by β-naphthols is reported, which provides a new strategy for the construction of chiral indole–terpenoid frameworks. This method affords indole-functionalized β-naphthalenone compounds bearing an all-carbon-substituted quaternary chiral center in excellent yields