Acid-Promoted Multicomponent Reaction To Synthesize 4-Phosphorylated 4 H -Chromenes.
Xiao-Hong WangXuan LiuYa-Wen XueXiao-Hong WeiYan-Bin WangQiong SuPublished in: The Journal of organic chemistry (2024)
An effective multicomponent reaction for the synthesis of 4-phosphorylated 4 H -chromenes via a tandem phosphorylation/alkylation/cyclization/dehydration sequence with water as the only byproduct was developed. Extensive mechanistic investigations involving in situ NMR experiments, time control experiments, and in situ HRMS experiment allowed us to elucidate the order of each subreaction to arrive at a complete understanding of the underlying mechanism of this multicomponent reaction. Mechanistic data confirm that the reaction begins with a phospha-aldol-elimination, followed by addition of a ketone enolate, intermolecular alkylation, intramolecular cyclization, and dehydration under acidic conditions.