Categories: C-O Bond Formation >
Synthesis of thiocarbamates
Stable and readily available N,N'-di-Boc-substituted thiourea can be used as a mild thioacylating agent when activated with trifluoroacetic acid anhydride. Through thioacylation of nucleophiles, such as amines, alcohols, thiols, sodium benzenethiolate, and sodium malonates, a series of thiocarbonyl compounds were prepared with good chemical selectivity and functional group tolerance.
B.-L. Yin, Z.-G. Liu, J.-C. Zhang, Z.-R. Li, Synthesis, 2010, 991-999.
The reaction of inexpensive, stable, and environmentally benign tetramethylthiuram disulfide (TMTD) with substituted phenols or alkyl alcohols in the presence of NaH provides N,N-dimethylthiocarbamates in good yields. This green and facile preparation avoids the use of toxic and corrosive N,N-dialkylthiocarbamoyl chlorides.
Z.-B. Dong, M. Wang, H. Zhu, X. Liu, C.-Z. Chang, Synthesis, 2017, 49, 5258-5262.
Electronically deactivated and/or sterically hindered substrates undergo the Newman-Kwart rearrangement (NKR) at around 300°C using modern microwave technology. In addition, several previously reported difficult examples were re-investigated, and the NKR under the reported conditions was found to be a reliable and high yielding reaction.
J. D. Moseley, P. Lenden, Tetrahedron, 2007, 63, 4120-4125.
Microwave technology has proven to be ideal for investigating the Newman-Kwart rearrangement (NKR) at high temperatures and facilitated the confirmation of many aspects of this valuable reaction. Comparisons between thermal and microwave results indicate no evidence of a significant microwave effect.
J. D. Moseley, R. F. Sankey, O. N. Tang, J. P. Gilday, Tetrahedron, 2006, 62, 4685-4689.