31557-57-0Relevant articles and documents
Stereodivergent Photoelectrocyclization Reactions of Bis-aryl Cycloalkenones: Intercepting Photoelectrocyclization Intermediates with Acid
Zhao, Xuchen,Song, Changqing,Rainier, Jon D.
supporting information, p. 8611 - 8614 (2019/11/03)
Described here are tandem photoelectrocyclization and [1,5]-hydride shift reactions of heteroaryl-containing bis-aryl cyclohexenone derivatives that give heteroaryl-substituted dihydrophenanthrenes. This Letter demonstrates that electrocyclization intermediates can be trapped with acid when the [1,5]-hydride shift is relatively slow. From a practical perspective, the observation that the acid-mediated reaction gives a divergent stereochemical outcome when compared with the reaction run under neutral conditions makes these transformations powerful.
Transition-metal-free decarboxylative halogenation of 2-picolinic acids with dihalomethane under oxygen conditions
Zhang, Xitao,Feng, Xiujuan,Zhang, Haixia,Yamamoto, Yoshinori,Bao, Ming
supporting information, p. 5565 - 5570 (2019/10/22)
A convenient and efficient method for the synthesis of 2-halogen-substituted pyridines is described. The decarboxylative halogenation of 2-picolinic acids with dihalomethane proceeded smoothly via N-chlorocarbene intermediates to afford 2-halogen-substituted pyridines in satisfactory to excellent yields under transition-metal-free conditions. This new type of decarboxylative halogenation is operationally simple and exhibits high functional-group tolerance.
Mild, visible light-mediated decarboxylation of aryl carboxylic acids to access aryl radicals
Candish,Freitag,Gensch,Glorius
, p. 3618 - 3622 (2017/07/11)
Herein we present the first example of aryl radical formation via the visible light-mediated decarboxylation of aryl carboxylic acids using photoredox catalysis. This method constitutes a mild protocol for the decarboxylation of cheap and abundant aryl carboxylic acids and tolerates both electron-rich substrates and those lacking ortho-substitution. The in situ formation of an acyl hypobromite is proposed to prevent unproductive hydrogen atom abstraction and trapping of the intermediate aroyloxy radical, enabling mild decarboxylation.