MPHT-Promoted Bromocyclization of ortho-Substituted Arylalkynes: Application to the Synthesis of 2-Substituted 3-Bromobenzofurans and -Benzo[b]thiophenes

作者：Jacubert Maud; Tikad Abdellatif; Provot Olivier; Hamze Abdallah; Brion Jean Daniel; Alami Mouad^*

来源：European Journal of Organic Chemistry, 2010, (23): 4492-4500.

DOI：10.1002/ejoc.201000529

• Enynes
• Alkynes
• Oxygen heterocycles
• Sulfur heterocycles
• Cyclization

A convenient and general approach to the synthesis of 2-substituted 3-bromobenzofurans and -benzothiophenes was developed. The procedure is based on the cyclization of ortho-substituted arylalkynes in the presence of N-methylpyrrolidin-2-one hydrotribromide (MPHT) as a soft and easy-to-handle electrophilic brominating reagent. Under mild reaction conditions, MPIIT promoted the bromocyclization of various enynes and diynes as well as arylalkynes to give 2-substituted 3-bromobenzofurans and -benzothiophenes in high to excellent yields Subsequent functionalization by palladium-catalyzed coupling reactions at the C-Br bond afforded general access to 2,3-disubstituted benzofurans and benzothiophenes of biological interest

• 出版日期2010-8