Synthesis 2002(7): 0879-0887
DOI: 10.1055/s-2002-28514
PAPER
© Georg Thieme Verlag Stuttgart · New York

A Mild Synthetic Procedure for the Preparation of N-Alkylated Sulfoximines

Carsten Bolm*, Christian P. R. Hackenberger, Oliver Simić, Marinella Verrucci, Dirk Müller, Frank Bienewald
Institut für Organische Chemie der RWTH Aachen, Professor-Pirlet-Strasse 1, 52056 Aachen, Germany
Fax: +49(241)8092391; e-Mail: Carsten.Bolm@oc.rwth-aachen.de;
Further Information

Publication History

Received 14 February 2002
Publication Date:
14 May 2002 (online)

Abstract

N-Alkylated sulfoximines have been synthesized in good yields by acylation of NH-sulfoximines followed by carbonyl reduction with complexed boranes. Enantiopure substrates react without racemization, and stereogenic centers originating from the acylating component are retained. If the acylation is performed by DCC coupling, this two-step procedure represents a rare example of a formal N-alkylation of sulfoximines under base-free conditions.

16

Both enantiomers of S-methyl-S-phenyl-sulfoximine (1a) are commercially available (Lancaster). To prepare 1a on a large scale we recommend the improved protocol described in ref. [5e]

17

The reaction was monitored by TLC after 4, 8, 16 and 36 hours and quenched when the product formation was complete.

20

For a discussion on this analogy see ref. [18]

21

The sulfoximines mentioned in entries 2 and 3 of Table [2] were prepared from TMS-protected (S)-S-methyl-S-phenyl-sulfoximine by metalation/alkylation sequence. Those shown in entries 4-8 (Table [2] ) were obtained by the procedure described in ref. [6] (MSH imination of the corresponding enantiopure sulfoxide).