[2+4] and [2+2] Cycloaddition Reactions of N-Sulfinyl Carboxylic Acid Amides with (CF3)2BNMe2. Crystal Structure ofcyclo-(CF3)2B-NMe2-S(=O)-N=C(p-CH3C6H4)-O
作者:David J. Brauer、Hans Bürger、Gottfried Pawelke、Jürgen Rothe
N-sulfinylacylamides R-C(=O)-N=S=O react with (CF3)(2)BNMe2 (1) to form, by [2+4] cycloaddition, six-membered rings cyclo-(CF3)(2)B-NMe2-S(=O)-N=C(R)-O for R = Me (2), t-Bu (3), C6H5 (4), and p-CH3C6H4 (5) while N-sulfinylcarbamic. acid esters R-O-C(=O)-N=S=O react with 1 to yield mixtures of six-membered (cyclo-(CF3)(2)B-NMe2-S(=O)-N=C(OR)-O) and four-membered rings (cyclo-(CF3)(2)B-NMe2-S(=O)-N(C=O)OR) for R = Me (6 and 9), Et (7 and 10), and C6H5 (8 and 11). The structure of 5 has been determined by X-ray diffraction.