229467-67-8Relevant academic research and scientific papers
Thiol mediated 5-(π-endo)ortho vinyl radical cyclizations
Montevecchi, Pier Carlo,Navacchia, Maria Luisa
, p. 201 - 219 (2007/10/03)
The radical reaction of benzenethiol with alkynes 1a-o carried out at 154 °C affords a mixture of thiol/alkyne adduct 3 and benzothiophene 5, deriving from vinyl radical intermediates 2 through hydrogen abstraction and 5-(π-endo)(orthocyclization onto the
Highly regio- and stereocontrolled synthesis of vinyl sulfides via transition-metal-catalyzed hydrothiolation of alkynes with thiols
Ogawa, Akiya,Ikeda, Takuma,Kimura, Kouichi,Hirao, Toshikazu
, p. 5108 - 5114 (2007/10/03)
Regio- and stereoselectivity in the hydrothiolation of alkynes with thiols in the presence of a variety of transition-metal catalysts is investigated in detail. Among the catalysts employed, RhCl(PPh3)3 exhibits excellent catalytic ability toward the anti-Markovnikov addition of thiols (ArSH) to alkynes (RC≡CH), which affords the corresponding vinylic sulfides (trans-RCH=CHSAr) regio- and stereoselectively. The reaction may proceed by the formation of hydrorhodium sulfide species (H-[Rh]-SAr) and probably via the subsequent hydrorhodation of alkynes to provide vinylrhodium intermediates (RCH=CH-[Rh]-SAr). In contrast, PdCl2(PhCN)2-catalyzed hydrothiolation of aromatic alkynes (ArC≡CH) takes place to give the corresponding Markovnikov adducts (R(ArS)C=CH2) with excellent regioselectivity, probably via thiopalladation of alkynes by palladium sulfide species (ArS-[Pd]-Cl), which may be formed by ligand-exchange reaction between PdCl2(PhCN)2 and ArSH. Furthermore, in the case of alkynes bearing propargylic protons (R'CH2C≡CH), a sequential addition/isomerization reaction occurs to provide the internal vinylic sulfides (R'CH=C(SAr)CH3) regioselectively. From the same starting materials (alkyne and thiol), therefore, the regioselectivity of hydrothiolation can be attained simply by changing the catalysts, i.e., RhCl(PPh3)3 and PdCl2(PhCN)2.
A New Syntethic Route to Vinyl Sulfides Utilizing the Reaction of (Phenylthio)carbenes with Nitrile Anions
Harada, Toshiro,Karasawa, Akio,Oku, Akira
, p. 842 - 846 (2007/10/02)
Reactions of nitrile anion (LiCR2R3CN) and (phenylthio)carbenes generated from 1-chloroalkyl phenyl sulfides (R1CH(Cl)SPh) 2a-e by the action of n-BuLi have been shown to be a useful synthetic route to vinyl sulfides (PhSC(R1)=CR2R3) 3a-k (34-91percent).The nucleophilic attack of the nitrile anion on the carbenic species gave the presumed intermediate β-(phenylthio)-β-lithionitrile, which eliminated LiCN to give the expected vinyl sulfides.The application of the present reaction to the synthesis of cyclic vinyl sulfides was successful: the decomposition of the dianion ofω,ω-bis(phenylthio)alkanenitriles (8b, 8c, 11, and 14) affording the corresponding 1-(phenylthio)cycloalkenes (9, 10, 12, and 15) in 12-87percent yields.
