D. A. Evans Diastereoaselective Hydrogenation: Acyclic Substrates Chem 206 Acyclic Allylic Alcohols P.Rh 93:7 anti syn>91:9 -CH2 R2 disfavored P-Rh- favored -CH syn T Anti: Syn Ratio psi H2 D1R=(CHa2CH52:48(35%) disfavored R=Ph 71:29() R=(cH3)2H12:88(8% D A Evans &M. M. Morrissey JACS 106, 3866 (1984) 21:79()R2 R1 CH2 OH Rh P P P Rh P Rh P P OH CH3 R2 R1 P Rh P C H R2 C H H C H H C R2 H Rh P P C OH R1 H Rh P P P Rh P OH C R1 H P Rh P OH C H R1 C OH H R1 CH3 CH2R2 CH3 CH2R2 H2 H2 H2 H2 R2 R1 CH3 OH R2 R1 CH3 OH OH CH3 R2 R1 OH CH3 R2 R1 R2 R1 CH2 OH OH CH3 R2 R1 T D T D O Ph CH3 N O O CH3 OH CH3 R R N CH2 OH CH3 O O CH3 Ph O Rh P P P Rh P C H H C R2 H C OH R1 H Rh P P P Rh P OH C R1 H CH3 CH2R2 H2 H2 R COXn CH3 OH CH3 COXn CH3 CH3 OH R R2 R1 CH3 OH OH CH3 R2 R1 640 psi H2 H2 Rh(DIPHOS-4)+ 25 : 75 (23%) 52 : 48 (35%) 71 : 29 (-) 13 : 87 (6%) 12 : 88 (8%) 21 : 79 (-) 93 : 7 94 : 6 93 : 7 9 : 91 8 : 92 6 : 94 Anti : Syn Ratio Hydroxy-Olefin R = CH3 R = (CH3)2CH R = Ph R = CH3 R = (CH3)2CH R = Ph 15 psi H2 + + low pressure syn anti H2 Rh(DIPHOS-4)+ + + anti > 93 : 7 syn > 91 : 9 D. A. Evans & M. M. Morrissey JACS 106, 3866 (1984) syn anti Acyclic Allylic Alcohols + + + + favored + disfavored disfavored favored + + + syn anti D. A. Evans Diastereoaselective Hydrogenation: Acyclic Substrates Chem 206