Formation of 5-Methylene-1,3-dioxepanes by the Reaction of 2,2,2-Triphenyl-1,2l5-oxaphospholanes with Paraformaldehyde
摘要:
Reaction of 2,2,2-triphenyl-1,2 lambda(5)-oxaphospholanes with paraformaldehyde yielded novel 7-membered cyclic methylene acetals (5-methylene-1,3-dioxepanes) in good yields. Phosphonium betaines reacted with paraformaldehyde to give new betaines, which further reacted with paraformaldehyde to afford olefins via Wittig reaction. The mechanism of this reaction was discussed.
The reaction of 6-methylene-l,3-dioxepanes derived from 3-hydroxyalkyltriphenylphosphonium salts and paraformaldehyde with trimethylsilyl trifluoromethanesulfonate in the presence of N,N-diisopropylethylamine yielded novel 4-formyltetrahydropyrans. 3-Methylenetetrahydropyrans were synthesized by the reaction of 4-hydroxyalkyltriphenyl-phosphonium iodides with DBU and paraformaldehyde. 2,3-Dihydro-
Reaction of 2,2,2-triphenyl-1,2 lambda(5)-oxaphospholanes with paraformaldehyde yielded novel 7-membered cyclic methylene acetals (5-methylene-1,3-dioxepanes) in good yields. Phosphonium betaines reacted with paraformaldehyde to give new betaines, which further reacted with paraformaldehyde to afford olefins via Wittig reaction. The mechanism of this reaction was discussed.