The palladium-tributylammonium formate reagent in the stereoselective hydrogenation, and stereo- and regioselective hydroarylation of alkyl 4-hydroxy-2-alkynoates: a route to substituted butenolides
The reaction of aryl iodides with alkyl 4-hydroxy-2-alkynoates in the presence of formic acid, tri-n-butylamine and a palladium(II) catalyst provides a convenient route to functionalized substituted butenolides through a one pot hydroarylation/cyclization reaction. In the presence of formic acid, tri-n-butylamine and a palladium(II) catalyst, alkyl 4-hydroxy-2-alkynoates undergo a one pot hydrogenation/cyclization
Cationic Rhodium(I) Complex-Catalyzed [3 + 2] and [2 + 1] Cycloadditions of Propargyl Esters with Electron-Deficient Alkynes and Alkenes
作者:Yu Shibata、Keiichi Noguchi、Ken Tanaka
DOI:10.1021/ja102418h
日期:2010.6.16
A cationic rhodium(I) complex, [Rh(cod)(2)]SbF(6), catalyzes the [3 + 2] cycloaddition of propargyl esters with dialkyl acetylenedicarboxylates in good yields, presumably through carbonyl-stabilized cationic rhodium(I) alkenylcarbene intermediates. The same rhodium(I) complex also catalyzes the [2 + 1] cycloaddition (cyclopropanation) of propargyl esters with N,N-disubstituted acrylamides in good yields
Manganese‐Catalysed C−H Activation: A Regioselective C−H Alkenylation of Indoles and other (hetero)aromatics with 4‐Hydroxy‐2‐Alkynoates Leading to Concomitant Lactonization
A manganese‐catalyzed C−H bond alkenylation of indoles at C2‐position with 4‐hydroxy‐2‐alkynoatesleading to concomitantlactonization under removable directing group strategy has been disclosed. This lactonization strategy exhibits regioselectivity, a broad substrate scope, and a good functional group tolerance furnishing the products in low to high yields. The regioselectivity is guided by the electronic
Rhodium(III)-Catalyzed C–H Activation: A Cascade Approach for the Regioselective Synthesis of Fused Heterocyclic Lactone Scaffolds
作者:Anil Kumar、Kandikere Ramaiah Prabhu
DOI:10.1021/acs.joc.9b03266
日期:2020.3.6
A Rh(III)-catalyzed cascade C-H activation; regioselective [4 + 2] oxidative annulation; and lactonization of aromatic acids, anhydrides, and acrylic acid derivatives with 4-hydroxy-2-alkynoates have been disclosed. This strategy leads to fused heterocyclic lactone scaffolds in a single step with moderate functional group tolerance and excellent site selectivity. Besides, in one step, an antipode of