Selective homo- and heterodehydrocouplings of phosphines catalyzed by rhodium phosphido complexes.
Reactions of the rhodium complex (dippe)Rh(eta3-CH2Ph) (1, dippe = iPr2PCH2CH2PiPr2) with ArPH2 (Ar = Ph, Mes) proceed via P-H oxidative additions to the phosphido complexes (dippe)Rh(mu-PHAr)2Rh(dippe) (3a, Ar = Ph; 3b, Ar = Mes). The corresponding reaction of Ph2PH occurs similarly, via the intermediate (dippe)Rh(PPh2)PHPh2 (4), to (dippe)Rh(mu-PPh2)2Rh(dippe) (3c). Complexes 3a-c and 4 are catalysts for the catalytic dehydrodimerizations of the corresponding phosphines to diphosphanes. Complex 1 is a more active dehydrocoupling catalyst, and substituent effects suggest that the active catalyst is mononuclear. Efficient dehydrocouplings of 2-EtC6H4PH2, 2-iPrC6H4PH2, and 2,4,6-iPr3C6H2PH2 were also observed. Complex 1 also catalyzes the heterocoupling of Ph2PH with PhSH (to Ph2P-SPh), and stoichiometric reactions in this system allowed isolation of (dippe)Rh(mu-SPh)2Rh(dippe) (6) and (dippe)Rh(SPh)PHR2 (7a, R2PH = MesPH2; 7b, R2PH = Ph2PH).
Han
Li-Biao
LB
Department of Chemistry, University of California, Berkeley, Berkeley, California 94720-1460, USA.
Tilley
T Don
TD
D002384:Catalysis; D006571:Heterocyclic Compounds / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D009942:Organometallic Compounds / Q000737:chemistry*; D010720:Phosphines / Q000737:chemistry*; D012238:Rhodium / Q000737:chemistry*; D013237:Stereoisomerism
D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; D010720:Phosphines; D012238:Rhodium