Syntheses of 1,2-Oxaphospholane 2-Oxides and 1,2-Oxaphosphole 2-Oxides

摘要

1,2-Oxaphospholane and 1,2-oxaphosphole 2-oxides, γ-phos-phonolactones and γ-phosphinolactones, also called γ-phos-tones and γ-phostines, are important five-membered 1,2-oxaphosphaheterocycles and crucial motifs of some biologically active compounds. Various synthetic methods of these 1,2-oxaphosphaheterocycles have been developed till now. They can be divided as cyclization, annulation, cycloaddition, ring expansion and contractions. The cyclizations mainly include intramolecular nucleophilic substitution of 3-haloalkylphos-phonic and phosphinic acid derivatives, esterification of 3-hydroxyalkylphosphonic/phosphinic acids, transesterification of alkyl 3-hydroxyalkylphosphonates/phosphinates, halocycliza-tion of alkyl alk-2/3-enylphosphonates, halocyclization of allenylphosphonic acid derivatives, the transition metal-catalyzed oxidative cyclizations of benzyl/2-meth-ylphenylphosphonic/phosphinic acids, and the Pd-catalyzed cyclization of γ-bromoalkyl phosphonates/phosphinates. The annulations covers [4 + 1] and [3 + 2] annulations. In this review, we have described various strategies and further development for the synthesis of 1,2-oxaphospholane and 1,2-oxaphosphole 2-oxides.