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. Sulfinyl amines are dienophile. They undergo [2+2] cycloaddition to ketenes.
According to X-ray crystallography, sulfinylamines have planar C-N=S=O cores with syn geometry.
Sulfinylamines can be made when thionyl chloride SOCl<sub>2</sub> reacts with a primary amine. Indeed, the parent thionylimide, HNSO, can be made that way at low temperature.
A frustrated Lewis pair, such as tris(tert-butyl) phosphine and tris(pentafluorophenyl)borane, can attach to the NSO chain to yield a R'<sub>3</sub>P=N<sup>+</sup>(R)SOB<sup>âÂÂ</sup>R"<sub>3</sub> compound.