One-Pot Reductive Sulfenylation and Thiocyanation of Carbonyl Compounds in Ionic Liquid Media

Abstract

The first example of an efficient one-pot reductive sulfenylation and thiocyanation of carbonyl compounds in environmentally benign ionic liquid (IL) media is reported. The process involves reduction of carbonyl compounds with NaBH₄ in the IL [bmim]BF₄ followed by I₂-catalyzed reaction of the resulting alcohols with aromatic / aliphatic thiols or ammonium thiocyanate in the same vessel to afford sulfides or thiocyanates, respectively, in excellent yields (78–93%). Notably, the protocol precludes the necessity to prepare and isolate the intermediate alcohols in a separate step as they are formed in situ, and the IL used can be recycled easily for further use without any loss of efficiency.

Keywords:

• Carbonyl compounds
• ionic liquids
• reduction
• sulfides
• thiocyanates

ACKNOWLEDGMENTS

We sincerely thank SAIF, CDRI, Lucknow, for providing microanalyses and spectra. Two of the authors (Garima and R. Kapoor) are grateful to the Council of Scientific Industrial Research, New Delhi, for the award of a junior research fellowship and research associate fellowship, respectively.

Notes

^a For the experimental procedure, see the Experimental section.

^b Time for the completion of the reaction as indicated by TLC.

^c Yield of isolated and purified product 3a.

^a Total time for the completion of steps (i) and (ii) as indicated by TLC.

^b Yield of isolated and purified product.

^c All compounds gave C, H, and N (if present) analyses within ±0.37% and satisfactory spectral (IR, ¹H NMR,¹³C NMR, and EIMS) data.