Study on the UV light-mediated fragmentation of 7-(2,4,6-trialkylphenyl-)7-phosphanorbornene 7-oxides in alcohols: New evidences on the mechanism

Preparative-scale photolyses of the title triisopropylphenyl-substituted co mpounds 1 and 4 at 254 nm, in the presence of alcohols, led to aryl-H-phosp hinates 3 in good yields. Reaction of the tri-tert butylphenyl derivative 5 was, however; accompanied by side reactions. The results of two series of competitive reactions are consistent with a mechanism involving a five-coor dinate adduct 8 of the alcohol on the P = O group of the phosphanorbornene oxides. (C) 2001 John Wiley & Sons, Inc.