Nitration of Silyl Allenes To Form Functionalized Nitroalkenes

An efficient nitration of silyl allenes with nitrogen dioxide radical, generated from NaNO2 and AcOH, to form alpha-nitro-alpha,beta-unsaturated silyl oximes has been developed. A similar nitration could be achieved by using Fe(NO3)(3)center dot 9H(2)O and FeCl3 center dot 6H(2)O, but different from the regioselective oxime formation, two regioisomeric chloride-trapped products were isolated with varying ratios depending on the steric bulk of the silyl group. A novel ring-closure reaction of alpha-nitro-alpha,beta-unsaturated silyl oximes upon treating with TBAF to form isooxazolidinone derivatives was also developed.