5‐endo‐dig Cyclization of O‐Propargyl Mandelic Acid Amides towards 2,5‐Dihydrofurans

Abstract

5-endo-dig cyclization of O-propargyloxyamides, obtained through a Passerini reaction mediated by boric acid and subsequent propargylation, affords 2,5-dihydrofurans in the presence of tert-butylate. The mechanism of the reaction was [a] Laboratoire de physico-chimie des microstructures et microsystèmes, 7658 Scheme 5. Attempted O-propargylation/cyclization sequence for 1k and 1l.

Visible light-induced oxidative esterification of mandelic acid with alcohols: a new synthesis of α-ketoesters

“…[29][30][31] In addition, the CvN double bond is constructed by reacting with p-toluenesulfonylhydrazine (Scheme 6b). [32][33][34] Notably, 3ab can also initiate cyclopropanation of chalcone for the synthesis of tetrasubstituted cyclopropane with a 1,2-cis-1,3-trans configuration in excellent yield (Scheme 6c). [35][36][37] Based on the available literature reports and our validation of the preliminary mechanism of the reaction, we introduced a possible reaction mechanism (Scheme 7).…”

“…29–31 In addition, the CN double bond is constructed by reacting with p -toluenesulfonylhydrazine (Scheme 6b). 32–34 Notably, 3ab can also initiate cyclopropanation of chalcone for the synthesis of tetrasubstituted cyclopropane with a 1,2- cis -1,3- trans configuration in excellent yield (Scheme 6c). 35–37…”