A simple and efficient palladium-catalyzed intramolecular carbonylativesynthesis of isocoumarins and phthalides from the easily available starting materials by employing phenylformate as a CO surrogate has been achieved. The approach affords target compounds in good to excellent yields with the advantages of lower toxicity, milder conditions, easy operation and wide functional group tolerance.
Palladium-Catalyzed Cross-Coupling of Benzyl Ketones and<i>α,β</i>-Unsaturated Carbonyl and Phenolic Compounds with<i>o</i>-Dibromobenzenes to Produce Cyclic Products
A number of carbonyl and phenolic compounds efficiently couple with o-dibromobenzenes in the presence of a palladium catalyst and a base to give the corresponding oxygen-containing heterocycles or carbocyclic compounds. Thus, from the reactions of benzyl phenyl ketones, 1-naphthols, and α,β-unsaturated aldehydes and ketones, benzofuran, benzopyran, benzocyclobutane, and indene derivatives, respectively, are produced selectively via the successive formation of C–C and C–O bonds or of two C–C bonds.
novel nickel catalyst for the reaction of tert-butyl isocyanide insertion was discovered. In this approach, 1,2-bis(diphenylphosphino)ethane (L3) serves as an efficient ligand, thereby allowing the preparation of lactones from (o-bromophenyl)phenylethanone derivatives. It is noteworthy that this is the first example of nickel acting as a metal catalyst in the reactions of tert-butyl isocyanide insertion