2,2 -hydroxy-1,1 -binaphthyl, optical

Tris[ (l S,2i )-6,6-dimethylbicylo[3.1.1]heptan-2-yl methyl]gallium reacts with ketones above room temperature, and optically active alcohols are obtained as main products (Scheme 145).438 LiGaH4, in combination with an S,0-chelate ligand, 2-hydroxy-2 -mercapto-l,T-binaphthyl (MTBH2), forms an active hydride catalyst for an asymmetric reduction of prochiral ketones with catecholborane. Enantiofacial differentiation is based on the steric requirement of the ketone substituents. Aryl//z-alkyl ketones are reduced in 90-93% ee and branched ketones RC(0)Me (e.g., R = Pr , oC6H11 Bu ) in 60-72% ee (Table 43).439 440... 

The pyrolysis of 2-hydroxy-2,2-diphenylefhylstibane gives 1,1-diphenylethylene (Scheme 14.57) [127]. The optically active (S)-(-i-)- and (R)-(-)-2,2 -bis[di(p-tolyl) stibano]-l,T-binaphthyls (BINASb) are used as chiral ligands in the Rh-catalyzed asymmetric hydrosilylation of acetophenone [128]. 

The kinetic resolution should be considerably enhanced if a chiral dicar-boxylic acid capable of ring formation to both 6-hydroxy groups of skyrin would be applied. We selected for this purpose 6,6 -dinitrodiphenic acid dichloride (32) which can easily be obtained in both enantiomeric forms. Reaction of (+)-(R)-binaphthol 31 with racemic 32 afforded the (+)-lactone 33, [a]p +213°, whereas the unreacted acid 34 showed a negative rotation (Scheme 7). Further investigations with the optically pure reagents indicated that (+)-(R)-31 forms only a lactone 33 with (+)-(R)-32 whereas (-)-( )-31 reacts only with (-)-( )-32. The same results were obtained with tetrachlorodiphenic acid dichloride. Similar observations have recently been published by Miyano and co-workers (ref. 20) for 1,1 -binaphthyl-2,2 -dicarboxylic dichloride. 

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