Asymmetric hydrogenolysis

Asymmetric hydrogenolysis of allylic esters with formic acid with satisfactory ee was observed[387], Geranyl methyl carbonate (594) was reduced to 570 with formic acid using l,8-bis(dimethylamino)naphthalene as a base and MOP-Phen as the best chiral ligand, achieving 85% ee. 

Asymmetric hydrogenolysis of epoxides has received relatively little attention despite the utility such processes might hold for the preparation of chiral secondary alcohol products. Chan et al. showed that epoxysuccinate disodium salt was reduced by use of a rhodium norbornadiene catalyst in methanol/water at room temperature to give the corresponding secondary alcohol in 62% ee (Scheme 7.31) [58]. Reduction with D2 afforded a labeled product consistent with direct epoxide C-O bond cleavage and no isomerization to the ketone or enol before reduction. 

Catalytic asymmetric hydrogenolysis of epoxides catalyzed by rhodium complexes has been reported [96,97]. 

Asymmetric hydrogenolysis of sodiiun dx-epoxysuccinates leads to malic acid derivatives which are useful building blocks in natural product synthesis [Eq. (11)] [60]. 

Marinating Pd/C with (lR,3S)-3-aminobomeol, (S)-2-hydroxymethylazetidine, and (l/ ,2S)-ephedrine produced useful chiral heterogeneous catalysts. These catalysts have been used for the asymmetric hydrogenolysis of benzyl /3-keto esters and benzyl enol carbonates to give chiral ketones in fair to good yield (ee) (Scheme These... 

Asymmetric hydrogenolysis of allylic carbonates was realized by the use of chiral ligand, (R)-MOP-Phen, with l,8-bis(dimethylamino)naphthalene (NRj) as a base to afford the optically active tenninal olefins (Scheme 7). 

Bakos, J., Orosz, A., Cserepi, S., Toth, 1. and Sinou, D., Chiral sulfonated phosphines. Rhodium(l)-catalyzed asymmetric hydrogenolysis of epoxides, /. MoL Cat. A Chem., 1997,116, 85. 

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