Pyridylseleno group in organic synthesis. Preparation and oxidation of .alpha.-(2-pyridylseleno) carbonyl compounds leading to .alpha.,.beta.-unsaturated ketones and aldehydes
Electrochemically driven desaturation of carbonyl compounds
作者:Samer Gnaim、Yusuke Takahira、Henrik R. Wilke、Zhen Yao、Jinjun Li、Dominique Delbrayelle、Pierre-Georges Echeverria、Julien C. Vantourout、Phil S. Baran
DOI:10.1038/s41557-021-00640-2
日期:2021.4
reagent. This electrochemically driven desaturation exhibits a broad scope across an array of carbonyl derivatives, is easily scalable (1–100 g) and can be predictably implemented into synthetic pathways using experimentally or computationally derived NMR shifts. Systematic comparisons to state-of-the-art techniques reveal that this method can uniquely desaturate a wide array of carbonyl groups. Mechanistic
长期以来,电化学技术因其与生俱来的可持续性而被誉为实现氧化还原反应的有效方法。作为一种基本的有机氧化,羰基去饱和是一种常用的转化方法,通过正式去除两个氢原子来解锁相邻的反应性。迄今为止,实现这种看似微不足道的反应的最可靠方法依赖于过渡金属(Pd 或 Cu)或基于 I、Br、Se 或 S 的化学计量试剂。在这里,我们报告了一种操作简单的途径,可以从烯醇硅烷和以电子为主要试剂的磷酸盐。这种电化学驱动的去饱和在一系列羰基衍生物中表现出广泛的范围,易于扩展(1-100 g),并且可以使用实验或计算得出的 NMR 位移可预测地实施到合成途径中。与最先进技术的系统比较表明,这种方法可以独特地使各种羰基去饱和。机械审讯表明基于自由基的反应途径。
A New Method for the One-Step Synthesis of α,β-Unsaturated Carbonyl Systems from Saturated Alcohols and Carbonyl Compounds
作者:K. C. Nicolaou、Y.-L. Zhong、P. S. Baran
DOI:10.1021/ja001825b
日期:2000.8.1
oxidation cascades (entry 5, three oxidations in one pot). A range of small (Scheme 1, and entries 6-8 and 14-16, Table 1) and large (entries 9 -13, Table 1) ring ketones and alcohols are easily and controllably (Scheme 1 and entries 8, 10, and 13, Table 1) oxidized. Substitution at the Rand â-sites (R, entry 14;â, entries 15 and 18) of the carbonyl system does not hinder the reaction, nor does it diminish
Palladium-catalyzed reactions of various 2-bromo-3-exo-methylenecycloalkenes with a stabilized nucleophile were examined. When the carbocycles were nine-membered or larger, the corresponding endocyclic allenes were isolated in excellent yields. In a reaction of the eight-membered cyclic substrate, initial formation of a cycloocta-1,2-diene derivative was detected; however, it dimerized slowly. The
Selective oxidation of secondary alcohols in the presence of primary ones has been achieved by the following sequences, (1) selective protection of primary alcohols with t-BuMe2SiCl, (2) oxidation of secondary alcohols with title reagents, and (3) deprotection of primary hydroxyls.