The bis(dicyclohexylphosphines) trans-C5H8(PCy2)2 (1) and trans-C7H10(PCy2)2 (11) (C5H8 = cyclopentane-1,2-diyl, C7 H10 = norbornane-2,3-diyl) were prepared by treatment of the bis(dichlorophosphines) trans-C5H8(PCl2)2 and trans -C7H10(PCl2)2 with CyMgBr. Oxidation with H2O2 in acetone gave the corresponding P,P′-dioxides, trans- C5H8[P(O)C y2]2 (2) and trans-C7H10[P(O)Cy2]2 (12) respectively. Effective optical resolution of 2 was achieved using (2S,3S )-(+)-di-O-benzoyl tartaric acid as a resolving agent. Heating (+)-2 and (-)-2 in neat Ph2SiH2 gave enantiopure 1. Reactions of 1 and 11 with (cyclo-C8H12)Pt(CH2CMe3)2 afforded the dineopentyls [transC5H8(PCy2)2]Pt(CH2CMe3)2 , 3, and [trans-C7H 10(PCy2)2]Pt(CH2CMe3)2 (13). These were further derivatized to [trans- C5H8(PCy2)2]PtH (CH2CMe3) (5), and [trans-C7 H10(PCy2)2]PtH (CH2CMe3) (15) by consecutive acidolysis (HCl or (1S)-(+)-camphor-10-sulphonic acid) and treatment with Na[BH (OMe)3] of the acido(organo) intermediates [trans-C5H8(PCy2)2]PtCl(CH2CMe3) (4) and [trans-C7H10(PCy2)2]Pt[O3SCH2C9H13 (O ) -(+ ) ]CH2CMe3 (14) (mixture of four diastereoisomers), so obtained. Thermolysis of 5 in cyclo-C6H12/PhC2H, C6H6, or Me3SiOSiMe3 led to smooth formation of [trans -C5H8(PCy2)2]PtH (R ), R = C2Ph (6 ), C6H5 (8), CH2SiMe2OSiMe3 (9), and [trans -C5H8(PCy2)2]Pt(η2-PhC ≡CH ) (7), respectively. Reactions of enantiopure complex 5, prepared from (cyclo-C8H12)Pt(CH2CMe3)2 and resolved bis(phosphine) 1 via (+ )-/(-)-3 and (+)-/(-)-4, with 2,2′-dimethylbinaphthyl and 2 ,2′ -di-t-butylbiphenyl ( 2 equiv. in cyclo-C6H12 at 68 °C) resulted in little optical induction.
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