Abstract The use of free radical reactions in organic synthesis has witnessed an extraordinary development recent years. When properly conceived, processes often exhibit many the properties desired by synthetic chemists, such as flexibility, mildness, and selectivity. Unfortunately, number synthetically useful radical‐generating systems is still limited, most applications have relied on tin hydride chemistry. Secondary O ‐alkyl‐ S ‐methyl xanthates, for example, eact with tributyltin to give...

Control of the radical polymerization acrylates, styrene and vinyl acetate has been achieved by using novel dithiocarbamates as reversible addition-fragmentation chain transfer agents. The key parameter for control with N,N-disubstituted (A) or cyclic (B) was found to be conjugation lone pair electrons nitrogen atom carbonyl aromatic groups.

Nitroalkenes, or their β-acetoxynitro precursors, react with α-isocyanoacetate esters in the presence of base to give high yields 5-unsubstituted pyrroles; some important pyrroles are easily synthesised by this method.

Xanthates and related derivatives have proved to be extremely useful for both inter- intramolecular radical additions. The broad applicability of the intermolecular addition un-activated olefins opens tremendous opportunities synthesis, since various functional groups can brought together under mild conditions complex structures rapidly assembled. presence xanthate in product is also a powerful asset further modifications, by non-radical pathways. Of special importance access highly...

The degenerative radical addition-transfer of xanthates onto alkenes allows the rapid assembly richly functionalized structures. Various families open-chain, cyclic, and polycyclic compounds can thus be readily accessed. Furthermore, process extended to synthesis or modification aromatic heteroaromatic derivatives by exploiting possibility using peroxides both as initiators stoichiometric oxidants. existing polymers controlled block what is now known RAFT/MADIX (reversible...

Abstract The capability of three chain‐transfer agents, O ‐alkyl‐ S ‐(1‐ethoxycarbonyl)ethyl xanthates (CH 3 CHCO 2 C H 5 )S(CS)OZ′, to control the free‐radical polymerization styrene and ethyl acrylate by MADIX process was examined. reactivity varied according following trend: Z′  CH < CF CH[P(O)(OEt) ]CF . This change in allowed a lowering polydispersity index from 2.0 for 1.15 case styrene. Evolution M w / n with conversion during presence X 1 , Reaction conditions: [EA] 0 = 4.6 [X]...

P. Delduc, C. Tailhan and S. Z. Zard, J. Chem. Soc., Commun., 1988, 308 DOI: 10.1039/C39880000308

The inability of the sp(3) boron in MIDA boronates to stabilize an adjacent radical makes possible efficient addition a wide array xanthates vinyl boronate, leading highly functionalized and diverse aliphatic organoboron structures. lack stabilization also allows exchange xanthate adducts with bromine. In one case, bromine was substituted generate cyclopropyl derivative.

New methods for the generation of iminyl radicals and other related nitrogen centered are described. Intramolecular capture such species allows an efficient yet simple construction containing heterocycles, especially relevant to field alkaloids. Iminyl can also be used trigger opening strained rings as cyclobutanones certain cyclopentanones or incorporated in radical cascades a synthetically useful manner.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRing opening induced by iminyl radicals derived from cyclobutanones: new aspects of tin hydride cleavage S-phenyl sulfenyliminesJean Boivin, Eric Fouquet, and Samir Z. ZardCite this: J. Am. Chem. Soc. 1991, 113, 3, 1055–1057Publication Date (Print):January 1, 1991Publication History Published online1 May 2002Published inissue 1 January 1991https://doi.org/10.1021/ja00003a057RIGHTS & PERMISSIONSArticle Views1224Altmetric-Citations125LEARN ABOUT...

Abstract

The observations and reasoning leading to the discovery of degenerative transfer xanthates related thiocarbonylthio derivatives are briefly described. A few synthetic applications presented, consequences on emergence RAFT MADIX polymerization technologies as well some mechanistic aspects discussed.

O-Octadecyl-S-trifluorothiolcarbonate is a cheap and storable crystalline source of trifluoromethanethiol that can be prepared in two steps on multigram scale from trifluoroacetic anhydride sodium O-octadecyl-dithiocarbonate (xanthate). It reacts directly with gramines or α-bromoketones -esters the presence KF pyrrolidine to give corresponding trifluoromethyl sulfides generally high yield.

Radical allylations represent effective routes to various alkenes, but date they have relied chiefly on organostannane derivatives and still suffer from significant limitations with respect the substitution pattern of starting allylating agent. Indeed, while substituents at β-position relative radical leaving group are well-tolerated, introduction α-substituents induces a major complication due rapid usually irreversible isomerization agents. Although number research groups made substantial...

Abstract Control of the free‐radical polymerization styrene was achieved using a series eight xanthates general structure RS(CS)OEt as reversible addition fragmentation chain‐transfer agents. The influence nature R leaving group explored. It found that transfer ability xanthate is markedly improved with increasing stability and its steric hindrance. Group strongly influences M n evolution profile during polymerization, but only polydispersities to small extent. cyanoisopropyl shown be best...

A short and efficient total synthesis of (±)-13-deoxyserratine (3) features a highly stereoselective intramolecular Pauson–Khand reaction 1 cascade radical cyclizations starting with the amidyl 2. The desired alkaloid 3 was thus obtained in ten steps an overall yield 12 %. THP=tetrahydropyranyl, TBS=tert-butyldimethylsilyl.