Cyanomethylation of Substituted Fluorenes and Oxindoles with Alkyl Nitriles
作者:Gang Hong、Pradip D. Nahide、Marisa C. Kozlowski
DOI:10.1021/acs.orglett.0c00160
日期:2020.2.21
cyanomethylenation from alkyl nitriles of sp3 C–H bonds to afford quaternary carbon centers is described. This oxidative protocol is operationally simple and features good functional group compatibility. This method provides a novel approach to highly functionalized fluorene and oxindole derivatives, which are commonly used in material and pharmaceutical areas. Control experiments provide evidence of a radical
Bond Dissociation Energies for Radical Dimers Derived from Highly Stabilized Carbon-Centered Radicals
作者:Mathieu Frenette、Carolina Aliaga、Enrique Font-Sanchis、J. C. Scaiano
DOI:10.1021/ol049111j
日期:2004.7.1
[reaction: see text] The temperature dependence of the dissociation of dimers formed from highly stabilized carbon-centered radicals has been examined. Analysis of the data yields the bond dissociation energy (BDE) for the central head-to-head C-C bond in these compounds. For example, for the dimer derived from 3-phenyl-2-coumaranone, BDE is 23.6 kcal/mol and the C-C bond length 1.596 A, a rather long
Most carbon-centered free radical antioxidants are generated through hydrogen abstraction. Disclosed herein are a new class of antioxidant precursor compounds of the formula A-B, wherein upon exposure of the compounds to an increase in temperature, the compounds undergo at least partial dissociation into free radicals Ao and Bo at least one of which may be functional as an antioxidant. Preferably, each of Ao and Bo is a carbon centered free radical.