Silyl Phosphites. 15. Reactions of Silyl Phosphites with α-Halo Carbonyl Compounds. Elucidation of the Mechanism of the Perkow Reaction and Related Reactions with Confirmed Experiments

Article abstract of DOI:10.1021/jo00323a024

The reactions of silyl phosphites, i.e., tris(trimethylsilyl)phosphite (1), diethyl trimethylsilyl phosphite (11), and bis(trimethylsilyl) ethyl phosphite (12), with a variety of α-halo carbonyl compounds gave the 1:1 carbonyl addition products (6, 13, and 14), enol phosphates (5 and 26), and/or 2-oxophosphonates (4 and 25).Substituents on the phosphites and the α-halo carbonyl compounds have influenced the product ratios.The results of these reactions strongly suggest that the Perkow reaction proceeds via an initial attack of phosphite on the carbonyl carbon of the α-halo carbonyl compound.Treatment of bis(trimethylsilyl) 1-<(trimethylsilyl)oxy>-2-halo phosphonates (6) with sodium methoxide in methanol followed by retrimethylsilylation gave bis(trimethylsilyl) 1,2-epoxy phosphonates (17), bis(trimethylsilyl) 2-oxo phosphonates (4), and bis(trimethylsilyl) methyl phosphate (21).On the other hand, diethyl 1-hydroxy-2-halo phosphonates (22) were converted by treatment with different bases to 1,2-epoxy phosphonates (23) predominantly in good yields.When some of tri-n-butyltin alkoxides were used as bases, enol phosphates (26) were obtained selectively.Several bis(trimethylsilyl) esters obtained in the above reactions were successfully converted to the corresponding monoanilinium salts in high yields by treatment with aniline-containing alcohols.