Boron Trifluoride-Promoted Reaction of Benzenesulphenanilides with Alkenes in Acetonitrile and Benzonitrile: Amidino- and Amido-sulphenylation of Alkenes
Benzenesulphenanilides (1) react at room temperature with alkenes in acetonitrile or benzonitrile in the presence of boron trifluoride-diethyl ether to give amidino sulphides (5; R=Me, Ph) in fair to good yields together with varying amounts of amido sulphides (7; R=Me, Ph) and arylamino sulphides (4), whereas at 100 deg C and in the presence of water 4'-nitrobenzenesulphenanilide affords amido sulphides (7; R=Me, Ph) as the main products.With cyclohexene a high selectivity for trans-addition is observed.With terminal alkenes the terminal sulphides are produced with high regioselectivity.The findings are consistent with a mechanism involving intermediacy of episulphonium ions (3) which result from alkene attack at the sulphur atom of an anilide-BF3 complex.
Benati, Luisa,Montevecchi, P. Carlo,Spagnolo, Piero
p. 2815 - 2818
(2007/10/02)
THERMAL REACTIVITY OF 4'SUBSTITUTED- AND 4'-SUBSTITUTED-2-PHENYL-BENZENESUPHENANILIDES
The thermal decomposition of 4'-nitro, 4'-H, and 4'-methoxy-benzenesulphenanilides in benzene and/or furan, and of 4'-substituted-2-phenylbenzenesulphenanilides ( 1d-1f ) in benzene, was found to proceed by two distinct pathways: ( i ) nucleophilic displacement by furan and/or another sulphenanilide unit and ( ii ) homolytic S-N bond fission to give sulphenyl and anilino radicals.An increase in the electron-withdrawning capability of the 4'-substituted favours the ionic pathway, whwreas the radical pathway is favoured by an increase in the reaction temperature.