Fragmentation of Bicyclic γ-Silyloxy-β-hydroxy-α-diazolactones as an Approach to Ynolides
摘要:
Medium-sized ynolides were prepared by the Lewis acid-mediated fragmentation of bicyclic gamma-silyloxy-beta-hydroxy-alpha-diazolactones in which the C beta-C gamma bond is the ring fusion bond. Although these lactone fragmentation substrates reacted somewhat less efficiently than their carbocyclic counterparts, the fragmentation provided 11-membered ynolides in up to 84% yield. Unlike prior fragmentations of similar substrates, elevated temperatures were required to obtain optimum yields of the ynolide products. The ynolides reported herein have ring sizes of 10 or 11, which are the smallest reported to date.
A Simple and Effective Method for α-Hydroxylation of β-Dicarbonyl Compounds Using Oxone as an Oxidant without a Catalyst
作者:Jun Yu、Jian Cui、Chi Zhang
DOI:10.1002/ejoc.201000940
日期:2010.12
Oxone has been found to be a highly efficient reagent for the introduction of a hydroxy group at the α position of a variety of β-dicarbonylcompounds in the homogeneous solvent mixture of water and 1,4-dioxane at 60 °C.
已发现 Oxone 是一种高效试剂,可在 60 °C 下在水和 1,4-二恶烷的均相溶剂混合物中在各种 β-二羰基化合物的 α 位引入羟基。
Highly Efficient CH Hydroxylation of Carbonyl Compounds with Oxygen under Mild Conditions
作者:Yu-Feng Liang、Ning Jiao
DOI:10.1002/anie.201308698
日期:2014.1.7
A transition‐metal‐free Cs2CO3‐catalyzed α‐hydroxylation of carbonylcompounds with O2 as the oxygen source is described. This reaction provides an efficient approach to tertiary α‐hydroxycarbonyl compounds, which are highly valued chemicals and widely used in the chemical and pharmaceutical industry. The simple conditions and the use of molecular oxygen as both the oxidant and the oxygen source make
描述了无过渡金属的Cs 2 CO 3催化的羰基化合物的α-羟基化,其中O 2为氧源。该反应为叔α-羟基羰基化合物提供了一种有效的方法,这些叔α-羟基羰基化合物是极有价值的化学物质,广泛用于化学和制药行业。简单的条件和使用分子氧作为氧化剂和氧源使该协议非常环保和实用。此转换是高效的,并且对叔C(sp 3)H键裂解具有高度选择性。
Aerobic α-hydroxylation of β-keto esters and amides by co-catalysis of SmI3 and I2 under mild base-free conditions
作者:Shun-Ming Yu、Kai Cui、Fei Lv、Zhen-Yu Yang、Zhu-Jun Yao
DOI:10.1016/j.tetlet.2016.05.052
日期:2016.6
A clean base-free α-hydroxylation of β-keto esters and amides has been developed, in which air was used as the oxygen source and SmI3 and I2 were applied as the catalysts, affording the corresponding α-hydroxylated 1,3-dicarbonyl products in good to excellent yields undermildconditions. Mechanism discussion shows that both oxygen atoms of dioxygen are utilized and incorporated into the product through
Universal remedy: The α‐hydroxylation of β‐keto esters and a range of other suitably substituted carbonyl compounds can be effected in the presence of IBX (2‐iodoxybenzoic acid). This novel reactivity underscores the importance of IBX as a universally applicable oxidizing agent.
Synthesis of Isatins through Direct Oxidation of Indoles with IBX-SO3K/NaI
作者:Stefan Kirsch、Angla Bredenkamp、Fabian Mohr
DOI:10.1055/s-0034-1380517
日期:——
Abstract The direct conversion of indoles into isatins is presented. The reagent mixture NaI/IBX-SO3K, containing a sulfonylated derivative of 2-iodoxybenzoic acid, was employed to trigger this oxidative process. Moreover, the synthetic route toward IBX-SO3K and the X-ray crystal structure of the title compound are described in great detail. The direct conversion of indoles into isatins is presented. The