Highly Stereoselective Access to Sulfur Derivatives Starting from Zinc ­Organometallics

Abstract

A number of organozinc reagents was found to react with tetramethylthiuram disulfide [(Me₂NCS₂)₂] giving dithio­carbamates with complete retention of configuration in the case of chiral compounds.

Key words

organozinc reagents - tetramethylthiuram disulfide - sulfur - chirality

References and Notes

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• 6a Langer F. Schwink L. Devasagayaraj A. Chavant P.-Y. Knochel P. J. Org. Chem.  1996,  61:  8229 
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4

The price of tetramethylthiuram disulfide is 30 Euro per kg (Aldrich).

8

This new redox reaction is actively investigated in our laboratories.

9

This lithium salt is readily prepared by treating TMTD (1) in THF with MeLi (1 equiv, -20 °C, 10 min).

10

Typical Procedure: Preparation of Myrtanyl Dimethyldithiocarbamate ( 4d).
A 25-mL Schlenk flask containing a solution of TMTD (1.00 g, 4.16 mmol) in CH₂Cl₂ (5 mL) was cooled to 0 °C, and bis(myrtanyl)zinc (510 mg, 1.5 mmol) [6] was added slowly at this temperature. The reaction mixture was stirred for 20 h at r.t. (a white precipitate of zinc dimethyldithiocarbamate formed), then was diluted with Et₂O (30 mL) and filtered. The precipitate was washed with Et₂O, the filtrate evaporated and the residue was purified by column chromatography (pentane-CH₂Cl₂), yielding myrtanyl dimethyldithiocarbamate as colorless crystals, mp 30-31 °C (70% yield, 673 mg).