Versatile reactivity of a rhodium(i) boryl complex towards ketones and imines

Abstract

The rhodium(I) boryl complex [Rh(Bpin)(PEt₃)₃] (1) reacts with the ketones α,α,α-trifluoroacetophenone and 9-fluorenone by insertion of the CO bond to give [Rh{η³-C(CF₃)(OBpin)C₆H₅}(PEt₃)₂] (4) and [Rh{η⁵-C₁₃H₈(OBpin)}(PEt₃)₂] (6), whereas the reaction with acetophenone leads to the formation of [Rh(H)(PEt₃)₃] (2), [Rh(OBpin)(PEt₃)₃] (3) and (E)-(Ph)CHCHBpin. Treatment of 1 with ketimines generates [Rh{η³-C₆H₅C(Ph)N(Ph)(Bpin)}(PEt₃)₂] (7), [Rh{(η³-C₁₂H₈)N(Ph)(Bpin)}(PEt₃)₂] (8) or [Rh{CPh₂N(H)(Bpin)}(PEt₃)₂] (9). The insertion of aldimines into the Rh–B bond gives access to [Rh[η³-CH{N(C₆H₁₃)Bpin}C₆H₅](PEt₃)₂] (11) or [Rh[η³-CH{N(Ph)Bpin}C₆H₅](PEt₃)₂] (12). The latter is converted into the C–H activation product [Rh{(C₆H₄)-o-N(Bpin)(CH₂Ph)}(PEt₃)₃] (13). Complex 13 reacts with B₂pin₂ to yield the boryl complex 1 and the amine PhCH₂N(Bpin)(C₆H₄-o-Bpin).