Aryl mesylate carbonylation

In 2008, Buchwald and colleagues developed an efficient procedure for the carbonylation of aryl chlorides, aryl tosylates and aryl mesylates [202-204]. Under their reaction conditions, carboxylic acid derivatives were prepared in good yields (Scheme 2.23). The advantages of this procedure are (1) l,3-bis(dicyclohexyl-phosphino)propane bis(tetrafluoroborate) as the ligand used is stable and easily available and (2) the reactions were carried out in a reaction tube under 1 bar of CO, avoid the using of autoclave. 

Pd-catalyzed carbonylation of aryl halides and triflates is a well-established process. Stephen L. Buchwald of MIT has now (/. Am. Chem. Soc. 2008,130, 2754) extended this transformation to much less expensive tosylates and mesylates such as 7. P-Amino acids have often been prepared from a-amino acids by Amdt-Eistert homologation. Geoffrey W. Coates of Cornell University has devised Angew. Chem. Int. Ed. 2008, 47, 3979) a more practical alternative, the direct Co-catalyzed carbonylation of an oxazoline 9 to the 2-oxazine-6-one 10. 

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