Enantiomeric recognition of alkyl phenyl sulfoxides by crystalline (R)-phenylglycyl-(R)-phenylglycine

The inclusion compounds of several alkyl phenyl sulfoxides by (R)-phenylglycyl-(R)- phenylglycine [(R,R)-1] were prepared by two different methods (sorption and crystallization). Alkyl phenyl sulfoxides entered crystalline (R,R)-1 with high S-enantioselectivity except for methyl phenyl sulfoxide which was recognized with high and reverse enantioselectivity (R-from in 92% eel. From the X-ray crystallographic study of an inclusion compound of bis[(o-methylsulfinyl)benzyl]ether (3) and (R,R)-1, it is deduced that the reversal of enantioselectivity was achieved by the confirmational change of phenyl groups on the dipeptide layer. (C) 1997 Elsevier Science Ltd.