DIFFERENTIATION AND ASSIGNMENT OF THE PROTON NMR SIGNALS IN THE BIS-MTPA ESTER OF MESO-ALPHA,ALPHA-DIMETHYL-1,4-BENZENEDIMETHANOL

NaBH4 reduction of one ketone in 1,4-diacetylbenzene followed by Amano PS catalyzed acylation of the R enantiomer, separation of the R aceta te from the S alcohol, and reduction of the remaining ketone in each w ith NaBD4, has provided two mixtures of monodeuterated diol diastereom ers: R,R(d) plus R,S(d) and S,R(d) plus S,S(d). Conversion of the unse parated diols into their bis-(R)-MTPA (Mosher's) esters has allowed th e NMR signals arising from the C-methyl groups at the R and the S ends of meso-alpha,alpha-dimethyl-1,4-benzenedimethanol bis-(R)-MTPA ester to be assigned unequivocally. Copyright (C) 1996 Published by Elsevie r Science Ltd