(2E,4R)-5-(1,1'-Biphenyl)-4-yl-4-(((1,1-dimethylethoxy)carbonyl)amino)-2-methyl-2-pentenoic acid → (2S,4S)-5-(Biphenyl-4-yl)-4-[(tert-butoxycarbonyl)amino]-2-methylpentanoic acid

Participants

Reaction Conditions

Reaction Steps

To a suspension of (E)-(R)-5-biphenyl-4-yl-4-tert-butoxycarbonylamino-2-methylpent-2-enoic acid [2(ii-a)] (20 g, 52 mmol) in degassed ethanol (100 ml) is added a solution of diiodo(p-cymene)ruthenium(II) dimer (0.215 g, 0.22 mmol) and (αS,αS)-2,2′-bis(α-N,N-dimethylaminophenylmethyl)-(R,R)-1,1′-bis[di(3,5-dimethyl-4-methoxyphenyl)phosphine]ferrocene (=Mandyphos SL-M004-2) (0.50 g, 0.47 mmol) in degassed ethanol (15 ml). The solution is degassed using vacuum and a pressure of 20 bar hydrogen is applied. The mixture is stirred at 25° C. for 15 h. The vessel is then purged with nitrogen. The solvent is removed in vacuo. The resulting solid is dried overnight at 50° C. under 1-50 mbar vacuum to afford the title compound [Ratio 2(i-a): 2(i-b) 7:93, as determined by HPLC analysis].

Provenance & Evidence