title: A radical process towards the development of transition-metal-free aromatic carbon-carbon bond-forming reactions.
abstract: Transition-metal-free cross-coupling reactions have been a hot topic in recent years. With the aid of a radical initiator, a number of unactivated arene C-H bonds can be directly arylated/functionalized by using aryl halides through homolytic aromatic substitution. Commercially available or specially designed promoters (e.g. diamines, diols, and amino alcohols) have been used to make this synthetically attractive method viable. This protocol offers an inexpensive, yet efficient route to aromatic C-C bond formations since transition metal catalysts and impurities can be avoided by using this reaction system. In this article, we focus on the significance of the reaction conditions (e.g. bases and promoters), which allow this type of reaction to proceed smoothly. Substrate scope limitations and challenges, as well as mechanistic discussion are also included.
authors.affiliation: State Key Laboratory of Chirosciences and Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (Hong Kong), Fax: (+852) 2364-9932.
authors.forename: Tek Long
authors.initials: TL
authors.lastname: Chan
authors.forename: Yinuo
authors.initials: Y
authors.lastname: Wu
authors.forename: Pui Ying
authors.initials: PY
authors.lastname: Choy
authors.forename: Fuk Yee
authors.initials: FY
authors.lastname: Kwong
mesh_terms: D000605:Amino Alcohols / Q000737:chemistry; D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D003959:Diamines / Q000737:chemistry; D005609:Free Radicals / Q000737:chemistry*; D028561:Transition Elements / Q000737:chemistry*
chemical_list: D000605:Amino Alcohols; D003959:Diamines; D005609:Free Radicals; D028561:Transition Elements; D002244:Carbon
keywords: CC bond formation; biaryl; cross-coupling; homolytic aromatic substitution; radical reactions