Pd^II-Catalyzed Oxidative Aldehyde-sp²C-H Functionalization and Cyclization Using NHC with Mild Oxidant DMSO for the Selective Synthesis of Esters, Sugar-Based Analogues, and β-Hydroxy Chromanones: An ¹⁸O-Labeling Study.

ABSTRACT: We assume formation of acyl-Pd^II-N-heterocyclic-carbene (NHC) organometalics for diverse C-O/O-C and C-C/C-O coupling catalysis of direct functionalization and cyclization reactions. We report the first use of dimethyl sulfoxide (DMSO) as an oxidant under an inert atmosphere to O₂-sensitive NHC for oxidative transformations. In situ generated imidazolium halides are utilized as a precursor of NHC and as a source of alkyl group for the sp²C-H functionalization of aldehydes to esters under mild conditions. In contrast to the reported NHC-catalyzed esterification strategies, the outstanding substrate scope of this mild catalysis approach is established through synthesis of thermally labile sugar-based chiral esters. Our competition experiments using var

SUBMITTER: Sarkar S 

PROVIDER: S-EPMC6044719 | biostudies-literature | 2016 Nov

REPOSITORIES: biostudies-literature