Reactions of elemental phosphorus and phosphine with electrophiles in superbasic media: XI. Phosphorylation of 4-methoxybenzyl chloride with elemental phosphorus and phosphine

4-Methoxybenzyl chloride reacts with elemental (red or white) phosphorus un der the conditions of phase-transfer catalysis (concentrated aqueous KOH, d ioxane, benzyltriethylammonium chloride, 85-90 degreesC, argon) to give as major product tris(4-methoxybenzyl)phosphine oxide in up to 45% yield. With white phosphorus at lower (70 degreesC) temperature this reaction yields m ainly bis(4-methoxybenzyl)phosphine oxide. Phosphine reacts with 4-methoxyb enzyl chloride in superbasic KOH-DMSO suspension, and under definite condit ions bis(4-methoxybenzyl)phosphine oxide is predominantly formed.