Alkene Isomerization–Hydroarylation Tandem Catalysis: Indole C2‐Alkylation with Aryl‐Substituted Alkenes Leading to 1, 1‐Diarylalkanes. Issue 5 (11th March 2014)

• Record Type: Journal Article
• Authors: Yamakawa, Takeshi; Yoshikai, Naohiko
• Is Part Of: Chemistry, an Asian journal. Volume 9:Issue 5(2014:May)
• Page Start: 1242
• Page End: 1246
• Publication Date: 2014-03-11
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1002/asia.201400135
• Languages: English
• ISSNs: 1861-4728

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>A cobalt‐<italic>N</italic>‐heterocyclic carbene catalyst generated from CoBr₂, imidazolium salt, and cyclohexylmagnesium bromide was found to promote the imine‐directed C2‐alkylation of indoles with nonconjugated arylalkenes through a tandem alkene isomerization–hydroarylation process, affording 1, 1‐diarylalkanes with exclusive regioselectivity. The feasibility of the tandem catalysis was demonstrated for allyl‐, homoallyl‐, and bishomoallylbenzene derivatives. The catalytic system is also applicable to a variety of β‐substituted styrene derivatives. Mechanistic experiments using deuterium‐labeled indole substrate and Grignard reagent provided insight into the cobalt‐mediated CH activation step, which likely involves exchange of the C2‐hydrogen atom of the former and the β‐hydrogen atoms of the latter.</p> </abstract>