SYNTHESES OF ROTATIONAL ISOMERS OF SUBSTITUTED 9-T-BUTYLTRIPTYCENES THAT CARRY AN OXYGEN SUBSTITUENT IN T-BUTYL GROUP AND OUTSTANDING STERIC EFFECTS OBSERVED IN THE SYNTHESIS OF AN INTERMEDIATE

The title rotational isomers were synthesized. Reduction of methyl 2-( 9-anthryl)-2-methylpropanoate caused difficulty due to severe steric e ffects. Thus the compound was converted to the free acid by treating i t with a lithium thiolate and the resulted acid was reduced to the cor responding alcohol with borane. The alcohol was protected as either an acetate or a silyl ether and was subjected to the reaction with a ben zyne. The resulted rotamers of triptycenes were separated by chromatog raphy. Rotamers that carry an acetoxy, a hydroxy, or a t-butoxy substi tuent were prepared.