A New Type of P-C and C-C Bond Cleavage Reactions in α-Trimethylsilyloxy-β-oxo Phosphonates and α-Ethoxy-β-oxo Phosphonates. The Synthesis of Unsymmetrical α-Hydroxy Ketones Utilizing 1:1 Carbonyl Adducts of Diethyl Trimethylsilyl Phosphite with Benzaldehyde

Article abstract of DOI:10.1246/bcsj.55.218

α-Lithiated diethyl α-(trimethylsilyloxy)benzylphosphonate underwent facile acylation with various acylating agents to afford the corresponding α-acylated products in good yields.On treatment with the α-acylated products with 1 M NaOH-EtOH (1:1, v/v) the P-C bond was cleaved with elimination of diethyl phosphate to give α-hydroxy ketones predominantly.On the other hand, when diethyl α-acyl-α-ethoxybenzylphosphonates were treated under the same conditions, they were rather stable and recovered.However, the prolonged alkaline treatment or the use of 4 M NaOH-EtOH (1:1 v/v) resulted in the C-C bond cleavage giving carboxylic acids and diethyl α-ethoxybenzylphosphonate in quantitative yields, respectively.The mechanisms of the above two reactions were proposed and discussed in connection with the Perkow reaction and related reactions.