Reactions of dimethoxycarbene with xanthates

Abstract

Dimethoxycarbene (DMC), generated by thermolysis of 2,2-dimethoxy-5,5-dimethyl–Δ³-1,3,4-oxadiazoline at 110 ^°C, in benzene in a sealed tube, reacted with most xanthates by formal insertion of the carbene into the S=C‒SR single bond. The reaction course is probably attack of the carbene at carbon of the C= S function, concomitant with (or followed by) migration of the SR group. The products, all new, are mixed orthoesters (two methoxy and one SR at the same carbon), a functional group that has been reported for one case only. In the case where the R group was CO₂Me, the reaction became complicated, probably from initial attack at the carbonyl group.

Keywords:

• Dimethoxycarbene
• Oxadiazole
• Thiocarbonyl compounds
• Xanthate
• Orthoester

Acknowledgements

A.W. E. gratefully acknowledges a fellowship from The Arab Fund Fellowship Program. All the authors thank NSERC for continued financial support.

Additional information

Notes on contributors

A. W. Erian

Visiting Professor from the University of Cairo.