Cyclic Phosphinates by the Alkylation of a Thermally Unstable 1-Hydroxy-1,2- Dihydrophosphinine 1-Oxide and A 3-Hydroxy-3-Phosphabicyclo[3.1.0]Hexane 3-Oxide

Abstract 1-alkoxy-1,2-dihydrophosphinine oxides 4 may be prepared by the reaction of 1-hydroxy-1,2-dihydrophosphinine 1-oxide 3 with alkyl halides. The best results were obtained in boiling acetone in the presence of K2CO3. The outcome of the alkylation of 3-hydroxy-6,6-dichloro-3-phosphabicyclo[3.1.0]hexane 3-oxide 5 was dependent on temperature. Butylation at 56 °C in acetone using K2CO3 afforded mainly the expected phosphinate 6, but an increase in the temperature led to opening of the cyclopropane ring, resulting in the formation of 1-butoxy-1,2-dihydrophosphinine oxide 4a as the major product. GRAPHICAL ABSTRACT