Organometallics in organic synthesis. Applications of a new diorganozinc reaction to the synthesis of C-glycosyl compounds with evidence for an oxonium-ion mechanism
作者:Alan P. Kozikowski、Toshiro Konoke、Allen Ritter
DOI:10.1016/s0008-6215(00)90882-6
日期:1987.12
features of a new organozinc-based substitution process [heteroatom-C-(R1,R2)-SPh + R3(2)Zn----heteroatom-C-(R1,R2,R3)], first discovered during a total synthesis of the alkaloid mycotoxin alpha-cyclopiazonic acid, are described. Phenyl thioglycosides were valuable substrates in studying the nature of this reaction process. Since these sulfur compounds are converted into C-glycosylcompounds with some
ethylmagnesium bromide and secondary amines, such as diisopropylamine (DIPA) or 2,2,6,6-tetramethylpiperidine (TMP) in diethyl ether, were examined. Diaryl sulfoxides were heated with the diisopropylaminomagnesium reagent in diethyl ether to give the corresponding diaryl sulfides in 42—52% yields. Sulfoxides bearing hydrogens at the α-positon only (RSOCH2R1) reacted with the tetramethylpiperidinomagnesium
Zinc-Catalyzed Synthesis of Dithioacetals through Double Hydrosulfenylation of Alkynes by Thiols
作者:Nobukazu Taniguchi、Kenji Kitayama
DOI:10.1055/s-0037-1610302
日期:2018.12
various solvents, and the corresponding products are obtained regioselectively. Dihydrosulfenylation of alkynes with thiols can also be achieved by using a zinc catalyst, and the reaction is preferentially promoted over monohydrosulfenylation. The reaction can also give dithioacetals regioselectively in excellent yields.
Direct conversion of carboxylic acids and carboxylic esters into S,S′-diphenyl acetals and phenyl sulfides with thexylphenylthioborane
作者:Sunggak Kim、Sung Soo Kim
DOI:10.1016/s0040-4039(00)96008-8
日期:1987.1
Reaction of carboxylic acids with thexylphenylthioborane in methylene chloride at room temperature gives S,S′-diphenyl acetals in high yields and carboxylic esters are converted into phenyl sulfides in the presence of zinc iodide under similar conditions.
elimination of arene- and alkanethiol from diaryl and dialkyl dithioacetals, in the presence of copper(I) or copper(II) salt plus tertiary amine, to produce the corresponding aryl and alkyl vinyl sulfides, respectively, has been studied. The employment of a combination of 2 mol equiv. of CuCl2 and 2 mol equiv. of N,N-diisopropylethylamine is most favorable.