Synthesis and structure of the chiral dialkyl phosphonate derivatives

The tandem asymmetric Michael addition/internal Michalis-Arbazov reaction o f compound 1 with nucleophilic trialkylphosphites has been investigated. Th e asymmetric reaction afforded optically pure 5-(1S)-bornyloxy-4-dialkyloxy -phosphonyl-3-halo-2(5H)-furanones 3a-3d at a mild condition in 69%-95% yie ld with d.e. greater than or equal to 98%. The chemical structure and confi guration of the chiral compounds 3a-3d were identified on the basis of thei r elemental analytical data and spectroscopic data, such as [alpha](D)(20), UV, IR, H-1 NMR, C-13 NMR, MS and X-ray crystallography.