6,6 -Dinitrodiphenic acid dichloride

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. 

Scheme 7. Reaction of rac. 6,6 -dinitrodiphenic acid dichloride (32) with (+)-(R)-binaphthol 31...

Scheme 8. Reaction of 6,6 -dinitrodiphenic acid dichloride with (+)-skyrin and (-)-flavomannin A...

---

See also in sourсe #XX -- [ , ]

---