ChemInform Abstract: Unusual Silylation of β‐Nitrobutyric Acid Methyl Ester with Trimethylchlorosilane.

Conjugated nitrosoalkenes

“…44 The reaction follows pathway a if the molecule 1 contains two electron-withdrawing groups (R 2 , R 4 ) such as CN or COOMe. In the latter case [pathway (b)], silyl nitronates 14 not only serve as the source of nitrosoalkenes 1 but also react with them according to the pattern of 1,2-addition to the nitroso group.…”

“…The fate of the resulting nitrosoalkenes 1 depends on their structure, in particular, on whether or not protons or electronwithdrawing groups are present at the g-position of the initial nitro compound. 44 The reaction follows pathway a if the molecule 1 contains two electron-withdrawing groups (R 2 , R 4 ) such as CN or COOMe. In the latter case [pathway (b)], silyl nitronates 14 not only serve as the source of nitrosoalkenes 1 but also react with them according to the pattern of 1,2-addition to the nitroso group.…”

“…Thus nitrosoalkene 50 for which concerted hydrogen [1,5]-shift is impossible due to steric reasons, is much less stable than compound 51, which contains no hydrogen atoms at C(3) (the half-life t 1/2 for the compound 50 in a dilute solution is 12 min, while that for the compound 51 is 900 min). 19 The scheme of transformation of the isoxazolinone 2 into the corresponding a,b-unsaturated oxime (see Section II.1) 21 and the synthesis of O-trimethylsilyl derivatives of the a,b-unsaturated oximes 16 (see Scheme 3) 44 have also been assumed to include stages involving the [1,5]-shift of hydrogen.…”