Taiwo O. Dairo, L. Woo
Feb 14, 2017
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0
Influential Citations
22
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Journal
Organometallics
Abstract
The insertion of carbenes derived from ethyl diazoacetate (EDA), methyl diazoacetate (MDA), methyl phenyldiazoacetate (MPDA), and methyl (p-tolyl)diazoacetate (MTDA) into the S–H bonds of aromatic and aliphatic thiols was catalyzed by (5,10,15,20-tetratolylporphyrinato)methyliridium(III), Ir(TTP)CH3, at ambient temperatures. Yields of the resulting thioether products were as high as 97% for aromatic thiols, with catalyst loadings as low as 0.07 mol %. Thiol binding to Ir(TTP)CH3 was measured at 23 °C by titration studies, providing equilibrium constants, Kb, ranging from 4.25 × 102 to 1.69 × 103 and increasing in the order p-nitrobenzenethiol < p-chlorobenzenethiol < benzenethiol < p-methylbenzenethiol < p-methoxybenzenethiol < benzyl mercaptan. Hammett plots were generated from the relative rates of S–H insertion, using different para-substituted benzenethiols in substrate competition experiments. In the presence of MDA and MTDA, the Hammett plots had slopes of −0.12 ± 0.01 and −0.78 ± 0.11, respectively...