Ring Opening of Methylbenzothiophenes and Methyldibenzothiophenes by Tris(triethylphosphine)platinum(0)

Abstract

The reaction of [Pt(PEt3)3], 1, with 3-methylbenzothiophene and 2-methylbenzothiophene afforded the thiaplatinacycles [(Et3P)2Pt(C,S-C9H8S)], 3 and 4, respectively. In the formation of both complexes (Et3P)2Pt has inserted into the C−S bond to the vinylic carbon. Complex 4 rearranges in solution to a dimeric thiaplatinacycle, 5, in which the platinum has moved from lying between the vinylic C−S bond into the aromatic C−S bond. Reaction of 1 with 4-methyldibenzothiophene gave a mixture of isomeric thiaplatinacycles [(Et3P)2Pt(C,S-C13H10S)], 6 and 7. The reaction of 1 with 4,6-dimethyldibenzothiophene containing some 1,9-dimethyldibenzothiophene led to the isolation of complex 9, [(Et3P)2Pt(C,S-C14H12S)]. This is derived from 1,9-dimethyldibenzothiophene, which is a byproduct in the preparation of 4,6-dimethyldibenzothiophene by a metalation pathway. The reaction of 1 with highly pure 4,6-dimethyldibenzothiophene gave the hydride complex, 10, in which (Et3P)2Pt has inserted into the C−H bond at the 3-position. The thiaplatinacycle cis-[(Et3P)2Pt(η2-C,S-C14H12S)], 8, was obtained by reaction of highly pure 4,6-dimethyldibenzothiophene with cis-[PtCl2(PEt3)2] and metallic sodium under hydrogen. X-ray structures of complexes 3, 5, and 9 are reported.

Ultra deep hydrodesulfurization of dibenzothiophene derivatives over NiMo/TiO2-Al2O3 catalysts

“…HDS pathways of 4,6-DMDBT. desulfurization of DBT using some organometallic complexes was also proposed [54,55].…”

Mechanistic Insights into the C–S Bond Breaking in Dibenzothiophene Sulfones

“…Compounds derived from the sulfone ring-opening ( 4 – 6 ) were detected; particularly, complex [(dippe)­Pt­(κ 2 - C , S -DBTO 2 )] ( 4 ) displays resonances in the 31 P­{ 1 H} NMR spectrum at δ 71.48 (s, 1 J Pt–P = 1941 Hz) and 55.29 (s, 1 J Pt–P = 2374 Hz), just as seen in closely related thiaplatinacycles derived from dibenzothiophenes . Table contains the 31 P­{ 1 H} NMR details for the sulfinaplatinacycles derived from DBTsO 2 .…”

Insertion of Pt into CH and CS bonds of thiophene derivatives. The X-ray crystal structure of a thiaplatinacycle of 3,6-dimethylthieno[3,2-b]thiophene

“…[24], 3-methylbenzothiophene [25], as well as 2-nitroand 3-chlorothiophene [14], reported in the literature.…”

“…Platinum-mediated C Ã/H activation in thiophenic substrates has been observed previously in the reaction of [Pt(PEt 3 ) 3 ] with 4,6-dimethyldibenzothiophene. In this case, the approach of the zerovalent metal complex to the C Ã/S bonds are blocked by the methyl substituents at C-4 and C-6 and the insertion reaction is thus directed to the C Ã/H bond at the 3-position [25].…”