Abstract
The reaction of various functionalized aryl and heteroaryl bromides with i-PrMgCl·LiCl produces highly reactive Grignard reagents complexed by LiCl, which react
with tetramethylthiuram disulfide [(Me2NCS2)2] leading to the corresponding dithiocarbamates in excellent yields. Various transformations
of the dithiocarbamates to thiols, thiol salts or thioethers have been demonstrated.
Key words
Grignard reactions - sulfur - chirality - lithium chloride - tetramethylthiuram disulfide
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Typical Procedure: Preparation of 3-Trifluoromethyl-phenyl Dimethyldithiocarbamate
(
4a).
A 25 mL Schlenk flask containing a i-PrMgCl·LiCl solution (10.5 mmol, 5.25 mL of 2.0 M solution in THF) was cooled to
0 °C, and 3-bromotrifluoromethylbenzene (10.0 mmol, 2.25 g) was added slowly at this
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into sat. NH4Cl solution (50 mL), the aqueous phase was extracted with CH2Cl2, the combined organic phases dried (MgSO4), evaporated in vacuo and the residue recrystallized from CH2Cl2-heptane. Yield 2.12 g (84%), mp 83-84 °C.
