Transition metal-free intramolecular regioselective couplings of aliphatic and aromatic C-H bonds.

ABSTRACT: Cross-dehydrogenative couplings of two different C-H bonds have emerged as an attractive goal in organic synthesis. However, achieving regioselective C-H activation is a great challenge because C-H bonds are ubiquitous in organic compounds. Actually, the regioselective couplings promoted by enzymes are a common occurrence in nature. Herein, we have developed simple, efficient and general transition metal-free intramolecular couplings of alphatic and aromatic C-H bonds. The protocol uses readily available aryl triazene as the radical initiator, cheap K2S2O8 as the oxidant, and the couplings were performed well with excellent tolerance of functional groups. Interestingly, ?-carbon configuration of some amino acid residues in the substrates was kept after the reactions, and the couplings for substrates with substituted phenylalanine residues exhibited complete ?-carbon diastereoselectivity for induction of the chiral ?-carbon. Therefore, the present study should provide a novel strategy for regioselective cross-dehydrogenative couplings of two different C-H bonds.

SUBMITTER: Tian H 

PROVIDER: S-EPMC4731807 | biostudies-other | 2016

REPOSITORIES: biostudies-other