75525-64-3Relevant academic research and scientific papers
Carbonylation of . New Intermediates in the CO Insertion Sequence
Anderson, Gordon K.,Cross, Ronald J.
, p. 1434 - 1438 (1980)
Phosphorus-31 n.m.r. studies of the reaction of trans- with carbon monoxide have led to the identification of several new intermediates and reaction pathways involved in the CO insertion process to produce trans-.Carbonyl addition forms a metastable five-co-ordinate compound in non-polar solvents, which eliminates a halide to form ionic species trans-X in polar solvents.Loss of PR3 from five-co-ordinate intermediates produces two isomers of which convert to the remaining isomer with Ph trans to PR3 before migration of Ph proceeds to form a benzoyl complex.A direct carbonyl insertion route from a five-co-ordinate intermediate also operates, independently of the phosphine elimination pathways, and this becomes the predominant pathways with more nucleophilic PR3 ligands.The use of elemental sulphur to remove PR3 from the reaction mixtures was instrumental in identifying some intermediates, and this method has potential synthetic value in replacing PR3 by weaker ligands at platinum.
