Selective C-C coupling at a Pt(iv) centre: 100% preference for sp-sp over sp-sp.

Dalton Trans

Department of Chemistry, Warwick University, Coventry, CV4 7AL, UK.

Published: April 2017

The oxidative addition of three different organic halides RX to the non-symmetric platinum(ii) mer coordinated dicyclometallated C^N^C complex 1 yielded short-lived six-coordinate platinum(iv) complexes 2(R) (R = Me, allyl, Bn), with the incoming groups trans across the platinum centre. A spontaneous reductive coupling reaction then occurred with, in each case, a completely chemoselective sp-sp coupling, and exclusively gave R-3, with the newly introduced R group bonded to the previously cyclometallated aryl ring. Following a recyclometallation reaction, the oxidative addition/reductive elimination cycle was repeated and gave the same selectivity. A one-pot route to doubly alkylating the aryl ring was developed. The observed selectivity might have been predicted on the normal basis of a steric barrier associated with non-flat sp hybridised groups, but we suggest that it arises from the stereochemistry at the metal, and the orientation of the ligands.

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http://dx.doi.org/10.1039/c7dt00328eDOI Listing

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