Pd-Catalyzed Decarboxylative Olefination: Stereoselective Synthesis of Polysubstituted Butadienes and Macrocyclic P-glycoprotein Inhibitors
作者:Bichao Song、Peipei Xie、Yingzi Li、Jiping Hao、Lu Wang、Xiangyang Chen、Zhongliang Xu、Haitian Quan、Liguang Lou、Yuanzhi Xia、K. N. Houk、Weibo Yang
DOI:10.1021/jacs.0c00078
日期:2020.6.3
The efficient and stereoselective synthesis of polysubstituted butadienes, especially the multifunctional butadiene, represents a great challenge in organic synthesis. Herein, we wish to report a distinctive Pd(0) car-bene-initiated decarboxylative olefination approach that enables the direct coupling of diazo esters with vinylethylene carbonates (VECs), vinyl oxazolidinones, or vinyl benzoxazinones
A catalytic, metal-free O–H bondinsertion of α-diazoesters in water in the presence of B(C6F5)3·nH2O (2 mol %) was developed, affording a series of α-hydroxyesters in good to excellent yields. The reaction features easy operation and wide substrate scope, and importantly, no metal is needed as compared with the conventional methods. Significantly, this approach further expands the applications of
在存在B(C 6 F 5)3 · n H 2 O(2摩尔%)的条件下,开发了水中无催化的α-重氮酸酯插入金属的O–H键,从而获得了一系列的α-羟基酯。好到极好的产量。该反应具有易于操作和广泛的底物范围的特点,重要的是,与常规方法相比,不需要金属。重要的是,这种方法进一步扩展了B(C 6 F 5)3在耐水条件下的应用。
Cyclopropenation of internal alkynylsilanes and diazoacetates catalyzed by copper(<scp>i</scp>) N-heterocyclic carbene complexes
作者:Thomas J. Thomas、Benjamin A. Merritt、Betsegaw E. Lemma、Adina M. McKoy、Tri Nguyen、Andrew K. Swenson、Jeffrey L. Mills、Michael G. Coleman
DOI:10.1039/c5ob02259b
日期:——
Copper(I) N-heterocycliccarbene (CuNHC) complexes are more catalytically active than traditional transition metal salts for the cyclopropenation of internal alkynylsilanes and diazoacetate compounds. A series of 1,2,3-trisubstituted and 1,2,3,3-tetrasubstituted cyclopropenylsilane compounds were isolated in good overall yields. An interesting regioselective and chemodivergent reaction pathway was
Blue Light-Emitting Diode-Mediated <i>In Situ</i> Generation of Pyridinium and Isoquinolinium Ylides from Aryl Diazoesters: Their Application in the Synthesis of Diverse Dihydroindolizine
作者:Saibal Sar、Souvik Guha、Tejas Prabakar、Debajit Maiti、Subhabrata Sen
DOI:10.1021/acs.joc.1c01209
日期:2021.9.3
1/2, aryl diazoesters 3, and acrylic ester/3-alkenyl oxindoles 5/6 provide various dihydroindolizines 7 to 9 in excellent yield. The principle of the strategy is photolytic generation of nitrogen ylidesfrom N-heteroarenes and aryl diazoesters and their subsequent [3 + 2] cycloaddition reaction with dipolarophiles. Detailed mechanistic analysis of the transformation through control experiments establishes
Palladium-catalyzed diastereoselective synthesis of 2,2,3-trisubstituted dihydrobenzofurans via intramolecular trapping of O-ylides with activated alkenes
An efficient palladium catalyzed diastereoselective synthesis of 2,2,3-trisubstituted dihydrobenzofurans has been accomplished in good yield as a single diastereomer. The transformation involves in-situ generation of oxonium ylide from 2-hydroxyphenyl substituted enone and diazo compound followed by intramolecular trapping via Michael addition. Successful integration of the developed method with intramolecular