24584-22-3Relevant articles and documents
Hindered Nucleophilic Displacement (SN2) Reactions of 2exo- and 2endo-Norbornyl Derivatives. Norbornane Series 4.
Grob, Cyril A.,Lutz, Erich
, p. 153 - 160 (1981)
The reactions of 2exo- and 2endo-norbornyl bromide (1 e and 2 e, respectively) in 90 percent ethanol with a large excess of potassium hydroxide, and 2exo-norbornyl-p-toluenesulfonate (1 g) with excess sodium thiophenolate in methyl cellosolve, have been studied.They obey the first order rate law and are zero order with respect to the base-nucleophile.However, the ratio of 1,2- and 1,3-elimination to exo-substitution products depends strongly on the base-nucleophile concentration.The extreme inertness of 2-norbornyl derivatives in displacement reactions is due to severe steric hindrance of rearside nucleophilic attack, a feature they have in common with other bi- and tricyclic molecules bearing nucleofugal groups adjacent to one or two bridgehead atoms.
An efficient radical procedure for the halogenation and chalcogenation of B-alkylcatecholboranes
Schaffner, Arnaud-Pierre,Montermini, Florian,Pozzi, Davide,Darmency, Vincent,Scanlan, Eoin Martin,Renaud, Philippe
supporting information; experimental part, p. 1163 - 1167 (2009/06/05)
An efficient formal anti-Markovnikov addition of HX (X = Cl, Br, I, SR and SeR) to olefins under mild reaction conditionsisdes cribed. The procedure isbas ed on the hydroboration of alkeneswith catecholborane. The conversion of the intermediate B-alkylcatecholboranesto the corresponding halides, sulfides and selenides is based on a common process, i.e., generation of a radical from the alkylborane followed by abstraction of a heteroatom from an aromatic sulfonyl reagent. The efficiency of these radical reactionsis remarkable. The mildness of the reaction conditions is well illustrated by the preparation of iodoalkanes. Despite the notorious reactivity of iodoalkanes under radical reaction conditions, no product degradation wasobs erved.
Photochemistry of phenyl thioethers and phenyl selenoethers. Radical vs ionic behavior
Kropp, Paul J.,Fryxell, Glen E.,Tubergen, Mark W.,Hager, Michael W.,Harris Jr., G. Davis,McDermott Jr., T. Paul,Tornero-Velez, Rogelio
, p. 7300 - 7310 (2007/10/02)
In analogy with alkyl iodides and bromides, the phenyt thio- and selenoethers 2a,b, 13a, 21b,c and 35 displayed competing radical and ionic photobehavior on irradiation in solution, via a mechanism thought to involve initial homolytic cleavage of the alkyl C-S or C-Se bond followed by electron transfer within the resulting radical pair cage (Scheme I). These are the first examples of ionic photobehavior to be recognized for the C-SAr and C-SeAr chromophores. The electronegatively substituted pentafiuorophenyl analogues 2c, 13b, and 21d displayed enhanced ionic photobehavior. By contrast, the 4-methoxyphenyl derivative 21a exhibited almost exclusively radical behavior. The sulfoxide (2R*,R*s)-21f displayed principally radical behavior, accompanied by epimerization at sulfur. The quantum yields for the disappearance of the 2-norbornyl ethers 21b and 21c were 0.53-0.64 in solution and rose to 0.89-0.95 in the presence of suspended fumed silica. Irradiation of the phenyl thioether 21b on silica gel resulted in nucleophilic trapping by surface silanol groups to afford covalently bound material (33), which afforded chloride 34 on treatment with SOCl2. Irradiation of phenyl thioethers 2a and 35, phenyl selenoether 2b, or C6H5SH in allyl alcohol solution afforded acetal 11, apparently via isomerization of some of the solvent to propanal (44) followed by acetalization. Irradiation of alcoholic solutions of aldehydes containing C6H5SH is a useful means of generating acetals under neutral conditions.
