Nitration of Silyl Allenes To Form Functionalized Nitroalkenes

Abstract

An efficient nitration of silyl allenes with nitrogen dioxide radical, generated from NaNO2 and AcOH, to form α-nitro-α,β-unsaturated silyl oximes has been developed. A similar nitration could be achieved by using Fe(NO3)3·9H2O and FeCl3·6H2O, 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 α-nitro-α,β-unsaturated silyl oximes upon treating with TBAF to form isooxazolidinone derivatives was also developed.

The Nitro to Carbonyl Conversion (Nef Reaction): New Perspectives for a Classical Transformation

“…[167] Desilylation of the oxime moiety using Bu 4 NF in the presence of AcOH generates the corresponding anion 271 which upon intramolecular conjugate addition and Nefr eaction of the formed nitronate anion affords isooxazolidinones 272.…”

Applications of Sodium Nitrite in Organic Synthesis

“…Nitration of the silylallenes 87 by NaNO 2 /AcOH under ultrasound irradiation resulted in α ‐nitro‐ α , β ‐unsaturated silyl oximes 88 which, underwent TBAF‐mediated ring‐closure to afford isoxazolidinones 89 as reported by Sabbasani and Lee (Scheme ) . The nitration of silylallenes to furnish a mixture of E/Z isomers was influenced by the size and electronic environment of the allenes and silyl moiety.…”

Applications of Allenylsilanes in Organic Synthesis

“…The reaction of chiral 2-silyl-substituted α-allenic alcohol 7 with aldehyde 6 in the presence of InBr 3 give rise to chiral homopropargylic alcohol 11. The reaction proceeds via formation of oxocarbenium ion 8, which undergoes a [3,3]-sigmatropic rearrangement to form the alcohol 11.…”

“…The reaction proceeds via formation of oxocarbenium ion 8, which undergoes a [3,3]-sigmatropic rearrangement to form the alcohol 11. The alcohol 11 is the key intermediate in the total synthesis of the natural product (+)-neopeltolide 12.…”

“…The reaction of chiral allenylsilanes with chiral aldehydes leads to the formation of mainly syn homopropargylic alcohols. 3 The reaction of chiral 3,3-disubstituted allenylsilane 3 with paraformaldehyde in the presence of TiCl 4 ·2THF generates chiral homopropargylic alcohol 4, which is the key intermediate in the total synthesis of (-)-histrionicotoxin 5.…”