to prepare aryllithium compounds having alkoxycarbonyl groups. To extend our studies on chemoselective lithiation, an important precursor for the synthesis of camptothecin was prepared using a halogen-lithium exchange reaction followed by an intramolecular 1,2-addition.
A practical, electrochemical method is developed for the direct dehydrogenative lactonization of C(sp2/sp3)–H bonds under external oxidant- and metal-free conditions, delivering diverse lactones, including coumarin derivatives with excellent regioselectivity. The scalable nature of this newly developed electrochemical process was demonstrated on a 40 g scale following an operationally simple protocol
Domino [Pd]-Catalysis: One-Pot Synthesis of Isobenzofuran-1(3<i>H</i>)-ones
作者:Lodi Mahendar、Gedu Satyanarayana
DOI:10.1021/acs.joc.6b01396
日期:2016.9.2
An efficient domino [Pd]-catalysis for the synthesis of isobenzofuran-1(3H)-ones is presented. The strategy shows broad substrate scope and is amenable to o-bromobenzyl tertiary/secondary/primary alcohols. Significantly, the method was applied to the synthesis of antiplatelet drug n-butyl phthalide and cytotoxic agonist 3a-[4′-methoxylbenzyl]-5,7-dimethoxyphthalide.
Oxidative Kinetic Resolution of Cyclic Benzylic Ethers
作者:Shutao Sun、Yingang Ma、Ziqiang Liu、Lei Liu
DOI:10.1002/anie.202009594
日期:2021.1.4
manganese‐catalyzed oxidative kinetic resolution of cyclic benzylic ethersthrough asymmetric C(sp3)−H oxidation is reported. The practical approach is applicable to a wide range of 1,3‐dihydroisobenzofurans bearing diverse functional groups and substituent patterns at the α position with extremely efficient enantiodiscrimination. The generality of the strategy was further demonstrated by efficient oxidative kinetic
Hydriodic Acid-Mediated Cyclization of α-Substituted Secondary 2-Ethenylbenzamides: Synthesis of 2-Substituted 2,3-Dihydro-3,3-dimethyl-1H-isoindol-1-ones and 3,3-Disubstituted (E)-1-(Arylimino)-1,3-dihydroisobenzofurans
for the preparation of 2‐substituted 2,3‐dihydro‐3,3‐dimethyl‐1H‐isoindol‐1‐ones 3 and 3,3‐disubstituted (E)‐1‐(arylimino)‐1,3‐dihydroisobenzofurans 6 has been developed. Thus, treatment of N‐alkyl(or aryl)‐2‐(1‐methylethen‐1‐yl)benzamides 2 with concentrated hydriodic acid (HI) in MeCN at room temperature afforded 3. Similar treatment of N‐aryl‐2‐(1‐phenylethen‐1‐yl)benzamide 5 with concentrated HI