《二硫醚合成方法.doc》由会员分享，可在线阅读，更多相关《二硫醚合成方法.doc（3页珍藏版）》请在金锄头文库上搜索。
1、Categories: S-S Bond Formation Synthesis of DisulfidesRecent LiteratureThe reaction of a thiol with 1-chlorobenzotriazole (BtCl) affords the benzotriazolated thiol (RSBt) without appreciable formation of the symmetrical disulfide. RSBt reacts with another thiol to form the unsymmetrical disulfide in
2、 a one-pot sequence without the need for toxic and harsh oxidizing agents.R. Hunter, M. Caira, N. Stellenboom, J. Org. Chem., 2006, 71, 8268-8271.R. Hunter, M. Caira, N. Stellenboom, J. Org. Chem., 2006, 71, 8268-8271.Unsymmetrical disulfides have been prepared from the corresponding thiols and bis-
3、(5,5-dimethyl-2-thiono-1,3,2-dioxaphosphorinanyl)disulfide under mild conditions with very good yields. This method can be applied to thiols bearing neutral, aromatic, basic or acidic functionalities with variable length of carbon chain.S. Antoniow, D. Witt, Synthesis, 2007, 363-366.A convenient met
4、hod for the synthesis of unsymmetrical disulfides under mild conditions in good to excellent yields is based on the use of a readily available organophosphorus sulfenyl bromide as activating agent. The unsymmetrical disulfides can be obtained for l-cysteine derivatives and thiols bearing neutral, ba
5、sic, or acidic functionalities.M. Szymelfejnik, S. Demkowicz, J. Rachon, D. Witt, Synthesis, 2007, 3528-3534.N-Trifluoroacetyl arenesulfenamides are effective precursors for the synthesis of unsymmetrical disulfides and sulfenamides. Reactions of N-trifluoroacetyl arenesulfenamides with thiols and a
6、mines gave the desired products in high yields within short reaction times.M. Bao, M. Shimizu, Tetrahedron, 2003, 59, 9655-9659.Thiols were effectively oxidized into disulfides by reacting with hydrogen peroxide in the presence of a catalytic amount of iodide ion or iodine.M. Kirihara, Y. Asai, S. O
7、gawa, T. Noguchi, A. Hatano, Y. Hirai, Synthesis, 2007, 3286-3289.Selective and quantitative conversion of thiols to disulfides was effected by dimethyl sulfoxide under mild conditions catalyzed by dichlorodioxomolybdenum(VI).R. Sanz, R. Aguado, M. R. Pedrosa, F. Arniz, Synthesis, 2002, 856-858.A mi
8、ld and efficient oxidation of various thiols affords the corresponding disulfides using 1,3-dibromo-5,5-dimethylhydantoin (DBDMH) as oxidant under both solution and solvent-free conditions.A. Khazaei, M. A. Zolfigol, A. Rostami, Synthesis, 2004, 2959-2961Substituent effect on the efficiency of desul
9、furizative rearrangement of allylic disulfides打印文件阅读人数：7我要评论Tags: 期刊：JOURNAL OF ORGANIC CHEMISTRY, 2008; 73 (16): 6127 作者：Li Z; Wang C; Fu Y; Guo QX; Liu L 通讯作者：Liu, L, Tsinghua Univ, Dept Chem, Key Lab Bioorgan Phosphorus Chem & Chem Biol Mini, Beijing 100084, Peoples R China.Substituent effect on
10、the efficiency of desulfurizative rearrangement of allylic disulfides | | Crich ligation is a new method for the functionalization of peptides and proteins under mild conditions. To more fully understand the mechanism of the ligation and to explore the effect of substitution on its efficiency, a sys
11、tematic theoretical study is carried out for the first time. It is found that the MP2 method wrongly predicts the substituent effect whereas the ONIOM(CCSD(T):B3LYP) method overestimates the free energy barriers by ca. 4 kcal/mol. Only the ONIOM(G3B3:B3LYP) method is found to be reliable as well as
12、feasible for studying the ligation. The rate-limiting step of the ligation is found to be the 2,3-sigmatropic rearrangement of the alkyl allyl disulfide, followed by an S(N)2 phosphine-mediated desulfurization. The S-S bond is significantly polarized during the rearrangement and, therefore, the reac
13、tion proceeds more rapidly in polar solvents. R-S and R-3 substitutions elevate the free energy barrier of the ligation, whereas the R-2 substitution does not exert a useful effect. Only the substitution at R-1 can effectively reduce the free energy barrier of the reaction to less than 20 kcal/mol (
14、a value required to allow the reaction to complete in minutes at 25 degrees C). Therefore, secondary and tertiary allyl alkyl disulfides can undergo the ligation at the room temperature. Marcus theory analysis indicates that the major factor for the retardation of the reaction by substituents at R-S
15、 and R-3 and for the acceleration by substituents at R-1 is the thermodynamic equilibrium between the disulfide and thiosulfoxide. To shift the equilibrium to favor the ligation, placement of substituents at R-1 is obligatory for alkyl allyl disulfides. Nonetheless, alkyl buta-2,3-dienyl disulfides may also undergo the ligation at room temperature without the help of the R-1 substituent.
