Silane, trimethyl[(methyleneoxidoamino)oxy]-

Physical properties

R1 = C5H11, R2 = H, R3Si = TBDMS: bp 80–90 °C/0.02 mmHg. R1R2 = (CH2)5, R3Si = TBDMS: bp 150 °C/0.01 mmHg. A more complete list of silyl nitronates is given by Torssell.

Uses

Trimethylsilyl Methanenitronate reacts with alkenes in a 1,3-dipolar cycloaddition reaction; undergo Bu4NF-mediated diastereoselective carbonyl addition to aldehydes; react with alkyllithium reagents to give oximes; oxidative coupling leads to 1,2-dinitro alkanes; cross coupling with silyl enol ethers or enamines gives β-nitro carbonyl derivatives; conversion of thiocarbonyl to carbonyl groups; can be converted into carbonyl compounds (cf. Nef reaction). It participates in the reactions of Silyl Nitronates with C–C Bond Formation, Reactions of Silyl Nitronates with Strong Base, Functionalization Reactions of Silyl Nitronates, Conversion of Thioketones to Ketones, Silyl Nitronate Reactivity Pattern, and other uses.

Preparation

A large number of silylation conditions can be applied to primary or secondary nitroalkanes,including: R3SiCl/Et3N (or Ag+ or Li2S), R3SiOTf, LDA/R3SiCl, R3SiCl/DBU, silylated amides, etc. The first reports were published by Ioffe, Tartakovskii, and their colleagues in the early 1970s. The silyl nitronates are isolated by nonaqueous workup and purified by bulb-to-bulb distillation, with the TBDMS derivatives being much more thermally stable than the TMS derivatives. From crystal structure analyses and NMR studies it is concluded that the silyl group migrates rapidly from one nitronate oxygen to the other and that the more stable configuration of silyl nitronates derived from primary nitroalkanes is (E).