Self-Condensation of Enaminodiones as a Method for Benzene Ring Construction: Synthesis of Diacyl-Substituted Phenols and Catechols
作者:Dmitrii L. Obydennov、Elena V. Chernyshova、Vyacheslav Y. Sosnovskikh
DOI:10.1021/acs.joc.9b00623
日期:2019.5.17
approach for the construction of the benzene core has been developed through self-condensation of available enaminodiones. Functionalized acyl-substituted phenols and catechols were obtained in 29–97% yields with high chemoselectivity under mild conditions. This base-promoted formal [4+2] annulation proceeds via cyclohexanone formation and involves the cascade transformation based on double Michael addition
Oxidative Ring-Opening Transformation of 5-Acyl-4-pyrones as an Approach for the Tunable Synthesis of Hydroxylated Pyrones and Furans
作者:Elena V. Steparuk、Ekaterina A. Meshcheryakova、Viktoria V. Viktorova、Maria V. Ulitko、Dmitrii L. Obydennov、Vyacheslav Y. Sosnovskikh
DOI:10.1021/acs.joc.3c00907
日期:2023.8.18
A selective and tunable approach for oxidation of 4-pyrones has been developed via ring-opening transformations leading to various hydroxylated oxaheterocycles. The first step of the strategy includes the base-catalyzed epoxidation of 5-acyl-4-pyrones in the presence of hydrogen peroxide for the effective synthesis of pyrone epoxides in high yields. The epoxides bearing the CO2Et group are reactive
通过开环转化开发了一种选择性且可调节的 4-吡喃酮氧化方法,产生各种羟基化氧杂环。该策略的第一步包括在过氧化氢存在下对 5-酰基-4-吡喃酮进行碱催化环氧化,以高产率有效合成吡喃酮环氧化物。带有CO 2 Et基团的环氧化物是反应性分子,可以通过去甲酰化进行吡喃酮和环氧乙烷开环,产生羟基化的2-吡喃酮或4-吡喃酮。酸促进的转化产生了 3-羟基-4-吡喃酮(产率 24-76%),而 K 2 CO 3催化的 2-乙酯基-4-吡喃酮环氧化物的开环过程则以醇的攻击形式进行。 C-3位置带有CO 2 Et基团,得到官能化的6-酰基-5-羟基-2-吡喃酮(产率27-87%)。2-芳基-4-吡喃酮环氧化物的碱催化反应随后进行环收缩和脱酰基化过程,产生 3-羟基呋喃-2-甲醛,产率 42-80%。3-芳酰色酮环氧化物在酸性和碱性条件下分别转化生成黄酮醇和3-羟基苯并呋喃-2-甲醛。制备的羟基化杂环化合物表现