P(n‐Bu)3 Catalyzed Reactions of Salicyl N‐Thiophosphinyl Imines with Allenylphosphonates: Synthesis of Phosphono‐Chromans

A phosphine [P(n-Bu)3]-catalyzed reaction for the synthesis of phosphono-chromans from allenylphosphonates and salicyl N-thiophosphinyl imines has been described and compared with reactions for phosphorus-free allenes. The products are (β,γ)-cyclized and are obtained in good yields (57–83%). A key product is characterized by X-ray crystallography.