Hydrazone Radical Promoted Vicinal Difunctionalization of Alkenes and Trifunctionalization of Allyls: Synthesis of Pyrazolines and Tetrahydropyridazines
作者:Xiao-Yong Duan、Xiu-Long Yang、Ran Fang、Xie-Xue Peng、Wei Yu、Bing Han
DOI:10.1021/jo4016908
日期:2013.11.1
achieved by using TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy) or DIAD (diisopropyl azodicarboxylate) as the hydrazone radical initiator as well as the carbon radical scavenger. Consequently, alkenes were difunctionalized to afford pyrazolines and tetrahydropyridazines via C–N forming 5-exo-trig and 6-exo-trig cyclizations, respectively, and allyls were trifunctionalized to afford pyrazolines via C–N forming
Rhodium-Catalyzed Chemo- and Regioselective Decarboxylative Addition of β-Ketoacids to Allenes: Efficient Construction of Tertiary and Quaternary Carbon Centers
作者:Changkun Li、Bernhard Breit
DOI:10.1021/ja411397g
日期:2014.1.22
A rhodium-catalyzedchemo- and regioselective intermolecular decarboxylative addition of β-ketoacids to terminalallenes is reported. Using a Rh(I)/DPPF system, tertiary and quaternary carbon centers were formed with exclusively branched selectivity under mild conditions. Preliminary mechanism studies support that the carbon-carbon bond formation precedes the decarboxylation and the reaction occurs