Formation of a C-C double bond from two aliphatic carbons. Multiple C-H activations in an iridium pincer complex

Summary, in English

The search for novel, atom-economic methods for the formation of C-C bonds is of crucial importance in synthetic chemistry. Especially attractive are reactions where C-C bonds are formed through C-H activation, but the coupling of unactivated, alkane-type C-sp3-H bonds remains an unsolved challenge. Here, we report iridium-mediated intramolecular coupling reactions involving up to four unactivated C-sp3-H bonds to give carbon-carbon double bonds under the extrusion of dihydrogen. The reaction described herein is completely reversible and the direction can be controlled by altering the reaction conditions. With a hydrogen acceptor present a C-C double bond is formed, while reacting under dihydrogen pressure leads to the reverse process, with some of the steps representing net C-sp3-C-sp3 bond cleavage. Mechanistic investigations revealed a conceptually-novel overall reactivity pattern where insertion or deinsertion of an Ir carbene moiety, formed via double C-H activation, into an Ir-C bond is responsible for the key C-C bond formation and cleavage steps.

• Author: Alexey Polukeev; Rocio Marcos; Marten S. G. Ahlquist; Ola Wendt
• Department/s: Centre for Analysis and Synthesis
• Publishing year: 2015
• Language: English
• Pages: 2060-2067
• Publication/Series: Chemical Science
• Volume: 6
• Issue: 3
• Links: http://dx.doi.org/10.1039/c4sc03839h
• Document type: Journal article
• Publisher: Royal Society of Chemistry
• Topic: Chemical Sciences
• Status: Published
• ISBN/ISSN/Other: ISSN: 2041-6539