Fragmentation‐Related Phosphonylation of Nucleophiles Utilizing P‐Alkyl 2,3‐oxaphosphabicyclo[2.2.2]octene 3‐oxide Precursors

New P‐alkyl 2,3‐oxaphosphabicyclo‐2.2.2]octene 3‐oxides were synthesized by the Bayer–Villiger oxidation of the corresponding 7‐phosphanorbornene 7‐oxides and were used as precursors for reactive alkylmetaphosphonates useful in the phosphonylation of alcohols. This is the first case that the reactivity of the two regioisomers formed by O‐insertion was differentiated and that the fragmentation‐related phosphonylation leading to phosphonic acid‐esters was achieved under microwave‐assisted conditions.