Five-, six-, and seven-membered rhodacycloalkanes from [RhI2(PPh3)(η5-C5Me5)] and BrMg–[CH2]n–MgBr (n= 4,5, or 6). Occurrence of carbon–carbon σ-bond cleavage in the preparation of the rhodacyclopentane derivative

Abstract

Reactions of [RhI₂(PPh₃)(η⁵-C₅Me₅)](1a) with the di-Grignard reagents BrMg–[CH₂]_n–MgBr (2; n= 5 or 6) led to the rhodacycloalkanes (3) and (4), respectively; reaction of (1a) with (2); (n= 4) gave the rhodacyclopentane (6) and the rhodium(I)–ethylene complex (5).