759.    DUPONT, G., PIGANIOL, P., AND VIALLE, J.  [The Oxo Reaction and Its Mechanism.]  Bull. Soc. Chim., France, 1948, pp. 529-532; Chem. Abs., vol. 42, 1948, p. 7232.

     Instead of the formation of the intermediate RCH-CHR-CO (I) when CO reacts

           |________|

with olefins in the presence of metallic carbonyls, the authors propose the existence of a combination of Ni or Co carbonyl with a reactive compound, A.H (H₂, H₂O, ROH, R₂NH, etc.).  This complex (II) reacts with the olefin in the presence of CO to regenerate the metal carbonyl and give III:

                          C:O

                        /      \

(OC)₃         Ni           A+CO+RCH : CHR→Ni(CO)₄ +

                      \

                       \

                         H

RCHCH₂R (III).  It is stated that number I has been

    |

AC : O

isolated from these reactions and that they do not occur unless A.H is present.  C₂H₂, CO and Ni (CO)₄ in the presence of a little HCl and alcohol at 50° give a 50% yield of polymers of CH₂ : CHCO₂Et and CH₂ : CHCO₂H.  1-Hexene, alcohol, CO, and Co(CO)₄ at 180° and 300 kg. pressure for 7 hours give 70% of a mixture of Me(CH₂)₅CO₂Et and Me(CH₂)₃ CHMeCO₂Et.  Cyclohexene under similar conditions gives 37% C₆H₁₁CO₂Et.  Replacing the alcohol with H₂O gives the acid.  Me hendecenoate gives a mixture of diesters.  Compounds with double bonds next to a tertiary C (carvomenthene and pinene) give little, if any, reaction.