Sulfinylamine

Sulfinylamines (formerly N-sulfinyl amines) are organosulfur compounds with the formula RNSO where R = an organic substituent. These compounds are, formally speaking, derivatives of HN=S=O, i.e. analogues of sulfur dioxide and of sulfur diimide. A common example is N-sulfinylaniline. The S-N bond in sulfinylamines is a dienophile. They undergo [2+2] cycloaddition to ketenes.

According to X-ray crystallography, sulfinylamines have planar C-N=S=O cores with syn geometry.

Preparation

Sulfinylamines can be made when thionyl chloride SOCl2 reacts with a primary amine. Indeed, the parent, thionylimide (HNSO), can be made that way at low temperature or in the gas phase. Under standard conditions it polymerizes. The corresponding trimethylsilyl compound, Me3SiNSO, is a stable liquid, albeit air-sensitive, and a common "−NSO" synthon.

Reactions

A frustrated Lewis pair, such as tris(tert-butyl) phosphine and tris(pentafluorophenyl)borane, can attach to the NSO chain to yield a R'3P=N+(R)SOB−R"3 compound.

Compounds