ChemInform Abstract: SYNTHESIS, PROPERTIES, AND CRYSTAL STRUCTURE OF SILYL NITRONATES (SILYL ESTERS OF ACI‐NITROALKANES): TOWARDS THE SN2 REACTION PATH WITH RETENTION OF CONFIGURATION AT SILICON

Abstract

SummaryAn efficient and flexible method for the preparation of silyl nitronates is described (see 1-10). NMR. spectral investigations indicate a rapid 1,3-silyl migration process, with an activation energy of about 10 kcal mol-'. X-ray crystallographic studies on the silyl nitronates 3 and 8 show structures that lean towards an SN2 retention pathway at silicon.Silyl nitronates (the trialkylsilyl esters of nitronic acids (= mi-nitroalkanes)) have been prepared and their chemistry as 1,3-dipolar reagents has been studied by Jofle et al. [l] and Torsell et al. [2]. The method of synthesis employed by Jo#e [ 11 was to heat the appropriate nitroalkane in N , 0-bis (trimethylsily1)acetamide; close to quantitative yields were claimed, but product purification proved to be a problem, with unavoidable contamination by excess silylating agent and acetamide by-products. Although only a limited range of compounds was described, both primary and secondary nitroalkanes could be employed [Equation (l)].

Electrophilically Activated Nitroalkanes in Reactions With Carbon Based Nucleophiles

“…To this end, strong Bronsted (Nakamura et al, 2007) or Lewis (Marce et al, 2016) acids could be employed. An alternative approach involves a tying the reactive aci-tautomer in acylated (Lehr et al, 1979), alkylated (Falck and Yu, 1992), or silated (Colvin et al, 1980) forms. Analysis of synthetic methods employing these unusual electrophilic synthons and their application in preparation of medicinally relevant scaffolds are analyzed in this review.…”

Efficient functional group transformations on a cyclic nitroalkene system

“…This compound gradually decomposed upon heating in vacuo, consistent with a previous report. 10 Oxidative cleavage of the C=N+ double bonds in (10) with aqueous potassium permanganate in the presence of magnesium sulphate14 provided the a-sulphenylated ketone (7) (81%). However use of hydrolytic techniques with various concentrations of aqueous sulphuric acid (0.01-4.5 M) for the Nef reaction7 gave (7) in lower yields (<6O%).…”