Nitro alkene Enantioselective reduction

Reduction of 1-nitro-1-alkenes with fermenting Baker s yeast proceeds enantioselectively to give optically active nitroalkanes (Eq. 3.53).81... 

Burk et al. showed the enantioselective hydrogenation of a broad range of N-acylhydrazones 146 to occur readily with [Et-DuPhos Rh(COD)]OTf [14]. The reaction was found to be extremely chemoselective, with little or no reduction of alkenes, alkynes, ketones, aldehydes, esters, nitriles, imines, carbon-halogen, or nitro groups occurring. Excellent enantioselectivities were achieved (88-97% ee) at reasonable rates (TOF up to 500 h ) under very mild conditions (4 bar H2, 20°C). The products from these reactions could be easily converted into chiral amines or a-amino acids by cleavage of the N-N bond with samarium diiodide. 

The reduction of carbon-carbon double bonds to single bonds has been studied with various substrates. For example, Ohta et al. demonstrated that the reduction of a number of 1-nitro-l-alkenes by fermenting baker s yeast was enantioselective, resulting in the formation of optically active 1-nitroalkanes as shown in Fig. 10.13(a).On the other hand, Fuganti et al. reduced a,/3-unsaturated y-lactones to produce enantiomerically pure (-1-)-(J )-goniothalamin (Fig. 10.13(b)), which shows central nervous system activity. They also performed the kinetic resolution of the corresponding embryotoxic epoxide with yeast. 8... 

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