Abstract Allenyl esters R 1 R 2 C= C= C (H) C (O) R (R= OMe) or amides (R= NEt 2) are formed with excellent selectivities and in good yields by carbonylation of propynyl and allenyl halides at 1–20 bar CO pressure in benzene, in the presence of MeOH or HNEt 2 and 1% of Pd (PPh 3) 4 or trans-Me 2 C= C= C (H) Pd (PPh 3) 2 Br. Possible organometallic intermediates are discussed.
