Carbenes, 18: Isomerization Reactions of Phosphoryl‐vinyl‐carbenes to Phosphorylated Cyclopropenes, Allenes, Acetylenes, Indenes, and 1,3‐Butadienes

Abstract

~Bestrahlung der durch Bamford-Stevens-Reaktion zuganglichen Phosphoryl-vinyl-diazomethane 5a -g in Benzol liefert die Carbene 6a -g, die ausschlieDlich intramolekular reagieren. Die Cyclopropenphosphonsaureester 8a -d und g sind die Hauptprodukte der Reaktion Regitz, Chem. Ber. 111, 1733 (1978.

Dialkyl 1-Alkynylphosphonates: a Range of Promising Reagents

“…[51] Thus, in the presence of a catalytic amount of para-toluenesulfonic acid, triethyl phosphite 4 reacts with propargyl alcohol in DMF at room temperature to give a mixture of diethyl allenylphosphonate 17 (R ϭ Et, R 1 ϭ R 2 ϭ R 3 ϭ H) (51%) and 1-propynylphosphonate 18 (R ϭ Et) (14%). The second variant [52] is based on the conversion of the allenylphosphonates 17 (R 1 , R 2 ϶ H, R 3 ϭ H) into 1-alkynylphosphonates 18 by a photochemically allowed [1,3s]-sigmatropic shift (in benzene, with 46Ϫ50% yields).…”

Perkow Reaction Induced C,C‐Bond Formation

“…Welter et al [5] obtained dimethyl cinnamoyl phosphonate ester in 38% yield by dissolving the acylchloride in benzene and adding the trimethyl phosphite. Aiming at an improved yield we added the acylchloride to an excess of trimethyl phosphite without a further solvent and obtained a crystalline material which is formally the trimer of the expected acyl phosphonate ester.…”