Synthesis and structure of the novel chiral 4-dialkyloxyphosphonyl-2(5H)-furanones

In this paper, we report that the tandem asymmetric Michael addition/internal Michalis - Arbazov reaction of 1 with nucleophilic trialkylphosphites afforded optically pure 5 - ( S) - l - menthyloxy - 4 - dialkyloxy - phosphonyl - 3 - halo - 2(5H) - furanones 4a similar to 44 in 86% similar to 95% yield with d. e. greater than or equal to 98%. The optically pure compound 4a similar to 4d were identified on the basis of their analytical data, such as [alpha](D)(20), UV, IR, H-1 NMR, C-13 NMR, MS and elemental analysis. The absolute configuration of the novel chiral phosphorous compound 4b was established by X - ray crystallography.