An approach for efficient synthesis of C-glycosyl amino acids, involving addition of in situ formed glycosyl radicals to α-imino esters, is described. Different from typical photoredox catalyzed reactions of imines, the new process follows a pathway in which α-imino esters serve as electrophiles in chemoselective addition reactions with nucleophilic glycosyl radicals. In addition, a new family of redox active esters of saccharides have been developed as C-glycosylation reagents for this process. The results of preliminary exploratory studies reveal that the reaction does not require the use of an external photosensitizer (PS), and that the Hantzsch ester (HE) can play a dual role as both a photoinduced single electron transfer (SET) and a hydrogen atom donor. The preparative power of the developed metal free protocol is highlighted by the mild nature of the reaction conditions, the highly stereoselectivity attending C-C bond formation and its applicability to C-glycosylations using both armed and disarmed pentose and hexose derivatives.

Visible light-mediated radical process for the synthesis of <i>C</i>-glycoamino acids

2019 Fall National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.

Visible light-mediated radical process for the synthesis of C-glycoamino acids