potassium tert-butylate; oxygen; phosphorous acid trimethyl ester 1) tBuOH, DMF; 2) acetic acid, THF, 1 h, ice-cooling; 40 h, room temp.; Yield given. Multistep reaction;

potassium tert-butylate; oxygen; phosphorous acid trimethyl ester 1) tBuOH, DMF, -25 deg C, 3.5 h; 2) acetic acid, THF, 1 h, ice-cooling; 40 h, room temp.; Yield given. Multistep reaction. Title compound not separated from byproducts;

Yield given. Multistep reaction;