FREE RADICAL CHAIN ELIMINATION REACTION (E<sub>RC</sub>1). CONVERSION OF VICINAL DINITRO COMPOUNDS OR β-NITRO SULFONES TO OLEFINS WITH TRIBUTYLTIN HYDRIDE
Vicinal dinitro compounds (1) or β-nitro sulfones (2) are converted to olefins in good yields on treatment with tributyltinhydride. This elimination proceeds by way of an electron transfer chain mechanism. The elimination from 1 is nonstereospecific and the elimination from 2 is stereospecific.
Reactions of methylenecycloalkanes and cycloalkylidenecycloalkanes with sulfur trioxide
作者:Ruud M. Schonk、Carel W. Meijer、Bert H. Bakker、Hans Cerfontain、Stephan Zöllner、Armin de Meijere
DOI:10.1002/recl.19931120705
日期:——
Reactions of methylenecycloalkanes 1a-4a and cycloalkylidenecycloalkanes 11a–14a with sulfurtrioxide were studied in the temperature range −60 to 25°C using dichloromethane as solvent and 1.5 mol equiv. of dioxane relative to the amount of SO3 as reactivity moderator. Methylenecyclooctane (1a), methylenecyclohexane (2a) and methylenecylopentane (3a) react with SO3 just like simple branched alkenes
Ring strain release as a strategy to enable the singlet state photodecarbonylation of crystalline 1,4-cyclobutanediones
作者:Gregory Kuzmanich、Miguel A. Garcia-Garibay
DOI:10.1002/poc.1902
日期:2011.10
is essential to slow down the combination of the intermediate acyl–alkyl biradical back to the starting ketone. Relatively long triplet acyl–alkyl biradical lifetimes give a chance for the loss of CO to occur. Looking for additional strategies to generate transient biradicals in solids, we studied the solid state photochemistry of four aliphatic, dispiro‐substituted 1,4‐cyclobutandiones (1a–d) that
Highly active salted low-valent titanium reagents for various SET induced reactions
作者:Shyam Rele、Subrata Chattopadhyay、Sandip K Nayak
DOI:10.1016/s0040-4039(01)02009-3
日期:2001.12
External addition of inorganic salts (Group I and II metal halides) to the preformed low-valenttitanium reagent A (TiCl3–Li–THF) dramatically enhanced its activity. The new reagents were used to carry out various SET reactions including McMurry's olefination at a faster rate even at ambient temperature.
Oxidative addition of carbon-oxygen and carbon-nitrogen double bonds to WCl2(PMePh2)4. Synthesis of tungsten metallaoxirane and tungsten oxo- and imido-alkylidene complexes
作者:Jeffrey C. Bryan、James M. Mayer
DOI:10.1021/ja00162a034
日期:1990.3
WCl 2 L 4 (1, L=PMePh 2 ) reacts rapidly with a variety of ketones and aldehydes to form bis(η2 -ketone) or bis(η2 -aldehyde) complexes WCl 2 (η2 -O=CRR') 2 L 2 (2,3). When the ketone is part of a five-membered ring (cyclopentanone, 2-indanone, etc.), 2 rearranges with loss of ketone to give tungsten (VI) oxo-alkylidene products, W(O)(CRR')Cl 2 L 2 (4) in high yield. The net reaction is insertion
WCl 2 L 4 (1, L=PMePh 2 ) 与多种酮和醛快速反应形成双(η 2 -酮)或双(η 2 -醛)配合物WCl 2 (η 2 -O=CRR') 2 L 2 (2,3)。当酮是五元环(环戊酮、2-茚满酮等)的一部分时,2 重排失去酮得到钨 (VI) 氧代亚烷基产物,W(O)(CRR')Cl 2 L 2 (4) 高产。净反应是将钨中心插入酮碳氧双键中,这是一种四电子氧化加成。插入 N-环戊基-对甲苯胺的碳-氮双键产生类似的亚氨基-亚烷基配合物 W(N-Tol)[C(CH 2 ) 4 ]Cl 2 L 2