Reaction of cyclic phosphites with haloacetones.

Abstract

Treatment of various cyclic phosphites (1), e.g., 2-methoxy-1, 3, 2-dioxaphosphorinane (1a), 2-methoxy-5, 5-dimethyl-1, 3, 2-dioxaphosphorinane (1b) and 2-methoxy-1, 3, 2-dioxaphosphorane (1c), with haloacetones (2) gave cyclic Arbuzov products (3), cyclic Perkow products (4), cyclic methylphosphonates (5), and acyclic products (6-8). Compound 1a gave all of the products (3a, 4a, 5a, 6ag, 7ag, 8ag). However, cyclic phosphites with substituents in the ring (1b, 1d) gave only the cyclic products (3-5). The five-membered ring phosphite (1c) yielded only the acyclic products (6cg, 7cg). Treatment of 1a with chloroacetone gave only the Perkow products (4a, 7ah). Cyclic phosphite (1f) with a 2-benzyloxy substituent afforded simply the cyclic products (3a, 4a, 9). A mechanistic interpretation of these reactions is presented.