Bifunctionalized allenes, Part XIX: Synthesis, electrophilic cyclization/addition, and coinage metal‐catalyzed cycloisomerization of phosphorylated 3‐(β‐hydroxy)allenes

Abstract

AbstractA convenient and efficient regioselective synthesis of phosphorylated 3‐(β‐hydroxy)allenes by an atom economical [2,3]‐sigmatropic rearrangement of the mediated propargyl phosphite or phosphinite which can be readily prepared via reaction of protected 5‐(tetrahydro‐2H‐pyran‐2‐yloxy)‐hex‐1‐yn‐3‐ol with dimethyl chlorophosphite or chlorodiphenyl phosphine, respectively, is described. This paper discusses a reaction of phosphorylated 3‐(β‐hydroxy)allenes with protected or unprotected hydroxy group involving 5‐endo‐trig cyclization or 2,3‐addition. Reaction of 3‐(β‐hydroxy)allenephosphonates with electrophiles that produces 2‐oxo‐2,5‐dihydro‐1,2‐oxaphospholes due to the participation of the phosphonate neighboring group in the cyclization is described. On the other hand, 5‐hydroxyhex‐(1E)‐enyl phosphine oxides were prepared by chemo‐, regio‐, and stereoselective electrophilic addition to the C2‐C3 double bond in the allenyl phosphine oxides and subsequent attack of the external (chloride anion) nucleophile. Phosphorylated 3‐(β‐hydroxy)allenes were smoothly converted into the corresponding 2‐phosphoryl‐5,6‐dihydro‐2H‐pyrans by using 5 mol % of coinage metal salt as catalyst in 6‐endo‐trig cycloisomerization reaction.