A cobalt‐catalyzed regioselective [4+2] annulation/lactonization reaction of benzamides with 4‐hydroxy‐2‐alkynoates is reported. This reaction utilizes air as an oxidant rather than metal salts. The method is operationally simple, mild, and sustainable. This protocol exhibits a broad substrate scope and compatible with a variety of functional groups furnishing the corresponding 1,4‐dihydrofuro[3,4‐c]isoquinoline‐3
据报道,苯甲酰胺与4-羟基-2-链烷酸酯发生钴催化的区域选择性[4 + 2]环化/内酯化反应。该反应利用空气而不是金属盐作为氧化剂。该方法操作简单,温和且可持续。该方案具有广泛的底物范围,并与提供相应的1,4-二氢呋喃[3,4- c ]异喹啉-3,5-二酮衍生物的各种官能团兼容,具有良好的产率和较高的区域选择性。
Gold-catalyzed ring expansions of 1-alkynylcyclobutanol derivatives via tandem hydration and α-ketol rearrangement
gold-catalyzed tandem hydration/α-ketol rearrangement of 1-alkynylcyclobutanol derivatives, leading to cyclopentanones bearing an α-hydroxy substituted quaternary center. In the presence of water, coordination of gold catalyst onto alkynyl moiety triggers hydration rather than a direct ringexpansion, which followed by unprecedented Au-catalyzed α-ketol rearrangement. The details and the scope of this method
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
作者:Tristan von Münchow、Suman Dana、Yang Xu、Binbin Yuan、Lutz Ackermann
DOI:10.1126/science.adg2866
日期:2023.3.10
Enantioselective redox transformations typically rely on costly transition metals as catalysts and often stoichiometric amounts of chemical redox agents as well. Electrocatalysis represents a more sustainable alternative, in particular through the use of the hydrogen evolution reaction (HER) in place of a chemical oxidant. In this work, we describe strategies for HER-coupled enantioselective aryl carbon-hydrogen
对映选择性氧化还原转化通常依赖昂贵的过渡金属作为催化剂,并且通常还依赖化学计量的化学氧化还原剂。电催化代表了一种更可持续的替代方案,特别是通过使用析氢反应 (HER) 代替化学氧化剂。在这项工作中,我们描述了使用钴代替贵金属催化剂进行不对称氧化的 HER 偶联对映选择性芳基碳氢键 (C-H) 活化反应的策略。因此,实现了羧酸酰胺的高度对映选择性碳-氢和氮-氢(C-H 和 N-H)环化,从而获得点和轴向手性化合物。此外,
Rh(<scp>iii</scp>)-catalyzed [3 + 2] spiroannulation of 2,3-dihydro-1,4-benzoxazines with 4-hydroxy-2-alkynoates through<i>ortho</i>-C–H bond functionalization
作者:Kommu Nagesh、Jagadish Manda、B. Sridhar、B. V. Subba Reddy
DOI:10.1039/d3ob00786c
日期:——
developed for the synthesis of highly rigid spirolactones in good yields with high regioselectivity. The reaction proceeds through a cascade of C–H activation followed by C–H annulation and lactonization. In this approach, two C–C and C–O bonds are formed in a single step. This is the first report on the spiroannulation of 2,3-dihydro-1,4-benzoxazines with 4-hydroxy-2-alkynoates.