Oxidation of Thiols with IBX or DMP: One-pot Access to Thiosulfonates or 2-Iodobenzoates and Applications in Functional Group Transformations

Abstract

Thiosulfonates are accessed by oxidation of feed-stock thiols using either DMP in DCM or IBX in MeCN at rt (~30 degree C). The protocol gives access to a variety of thiosulfonates in good to excellent yields from both aromatic and aliphatic thiols. The reaction with DMP is found to be better than IBX in terms of reaction rate and conversion, whereas the oxidation with DMP requires lower equivalent than IBX. Benzyl thiols are however found to follow a different reaction pathway when treated with DMP; O-benzyl esters of o-iodobenzoates were isolated. The 1H NMR spectroscopic monitoring studies for the IBX-mediated oxidation of thiol found disulfide as an initial intermediate, which is proposed to undergoes a cascade of oxidations to produce thiosulfonate

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Supplementary material

Oxidation of Thiols with IBX or DMP: One-pot Access to Thiosulfonates or 2-Iodobenzoates and Applications in Functional Group Transformations
This is a very good selective oxidative transformation of thiols to thiosulfonates and benzyl benzoates. To the best of our knowledge, this is the first report that offers the direct challenging transformation of benzyl thiols to corresponding esters, alcohols and aldehydes through a tandem process. Herein, we have used hypervalent iodanes (DMP, IBX, and IBA) which are considered as a mild oxidizing reagent with eco-friendly attributes.

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Dr Ajeet Chandra
Dr. A. Chandra obtained his M.Sc. from University of Allahabad, in 2012. He joined as a Pre Ph.D. research experience in peptide synthesis at Indian Institute of Technology, Delhi in 2013 and later, moved to IIT Kanpur in 2014 for doctoral studies in organic chemistry. After completing his Ph.D. in 2020, he moved to IIT Bombay, for postdoctoral research, where he was involved in the development of new synthetic methodologies using sulfonylphthalide reagents and asymmetric catalysis as well. Currently, he is shifting to the Kyung Hee University, South Korea, for another post-doctoral stint, to design and synthesize organic materials for material chemistry.
Dr. Keshaba N. Parida
Keshaba N. Parida received B.Sc. (2006) and M.Sc. (2008) in chemistry from Sambalpur University. In 2009, he joined IIT Kanpur for doctoral studies under Prof. J. Narasimha Moorthy. After obtaining a Ph.D. in organic chemistry, he gained postdoctoral research experiences from Ariel University (Israel), the University of Arizona (USA) and IISER Trivandrum (India). At present, Keshaba is a CSIR-SRA fellow (Pool Scientist) at IISER Trivandrum, India. His research interest is based on organic synthesis.