Fluoride-Mediated Dephosphonylation of α-Diazo-β-carbonyl Phosphonates

The possibility of fluoride-mediated selective dephosphonylation of alpha-diazo-beta-carbonyl phosphonates such as the Ohira-Bestmann reagent has been proposed and executed. The resulting alpha-diazocarbonyl intermediates undergo a (3 + 2)pcycloaddition at room temperature with conjugated olefins and benzynes. Interestingly, under the current conditions, the resulting cycloaddition products underwent either N-acylation (with excess alpha-diazo-beta-carbonyl phosphonates) or Michael addition (with conjugated olefins).