No abstract

Bis(beta-trimethylsilylethanesulfonyl)imide (SES(2)NH) can be easily prepared in 85% yield by alkylation of the trianion of bismethanesulfonimide with 2 equiv of commerically available (iodomethyl)trimethylsilane. This synthon undergoes effective Mitsunobu alkylation reactions with both primary and secondary alcohols to afford the corresponding bis-SES imides. These imides can be selectively cleaved to the mono-SES-protected amines, and in addition undergo a one-pot cleavage/N-alkylation to afford SES derivatives of secondary amines.

Pyrazoles and 5-Aminopyrazoles. -A convenient one-step synthesis of β-tosylethylhydrazine from p-tolyl vinyl sulfone is developed. This hydrazine reacts with both 1.3-diketones and conjugated ynones to provide a variety of N-tosylethyl-protected pyrazoles in good yields and good regioselectivity. In addition, hydrazine (II) condenses with β-ketonitriles and β-aminoacrylonitriles to afford 5-aminopyrazoles (XII) and (XVI). The N-TSE protecting group can be removed by exposure to base under mild conditions. -(DASTRUP, D. M.; YAP, A. H.; WEINREB*, S. M.; HENRY, J. R.; LECHLEITER, A. J.; Tetrahedron 60 (2004) 4, 901-906;

Organo-silicon compoundsOrgano-silicon compounds S 0060 Preparation of Bis(β-trimethylsilylethanesulfonyl)imide and Its Use in the Synthesis of Protected Amine Derivatives. -Treatment of imide (I) with the iodide (II) results in efficient formation of title compound (III). Under Mitsunobu conditions it readily reacts with primary and secondary alcohols to afford protected amines of type (V). In the presence of CsF the latter undergo selective monodeprotection. A one-pot monodeprotection/N-alkylation is also possible. The remaining trimethylsilylethanesulfonyl group of the alkylated products can be removed with CsF at high temperature. -(DASTRUP, D. M.; VANBRUNT, M. P.; WEINREB*, S. M.; J. Org. Chem. 68 (2003) 10, 4112-4115;