1,3-dipolar cycloaddition of trimethylsilyl azide to propynals and dimerization of 1H-1,2,3-triazole-5-carbaldehydes to tricyclic bis-hemiaminals

Abstract

Reactions of trimethylsilyl azide with 3-trimethylsilyl-2-propynal and 2-propynal were studied. X-Ray analysis of the molecular structure of 4-trimethylsilyl-1H-1,2,3-triazole-5-carbaldehyde showed that the carbonyl group appears in the s-cis conformation with respect to the double C=C bond in the heteroring. The effect of the temperature and polarity of the medium on the ability of 1H-1,2,3-triazole-5-carbaldehyde to undergo dimerization to tricyclic bis-hemiaminals was examined by IR and 1 H NMR spectroscopy.

Cascade Reactions of Me3Si‐Substituted Imidazolidine‐1,3‐Diols with PbO2, Including Oxidation of the Corresponding Diol and Subsequent Elimination of the Trimethylsilyl Fragment

“…The reaction of aldehyde 9 [6] with bis(hydroxylamine) 5 in MeOH (Scheme 3) did not lead to the formation of expected imidazolidine-1,3-diol 10. This was attributed to the fact that under these conditions, 10 is spontaneously dehydrated into 4,4,5, (12) .…”

“…General Methods: 4,4,5,5-Tetramethyl-2-[2-(trimethylsilyl)ethynyl]-imidazolidine-1,3-diol [2] (1), 4-[(trimethylsilyl)ethynyl]benzaldehyde [4] (4), 1H-1,2,3-triazole-5-carbaldehyde [6] (9), N,NЈ-(2,3-dimethylbutane-2,3-diyl)bis(hydroxylamine) [11,12] (7), and 4-(trimethylsilyl)-1H-1,2,3-triazole-5-carbaldehyde [6] (13) were prepared according to the published procedures. All the solvents used were reagent quality.…”

Silicon- and germanium-substituted propynals as ambident electrophiles for the design of new heterocycles and polyfunctional acetylenes

“…154 We demonstrated a regiospecificity of addition of azidotrimethylsilane to propynals with the formation of triazoles 30a and 30i in 75 and 74% yield, respectively. 27 The reaction of propynals 2a and 2i with equimolar amount of Me 3 SiN 3 was carried out in toluene, respec tively, at 90-95 °С for 32 h and in THF at -30-25 °С for 7 days (Scheme 16).…”

One-Pot Synthesis of 3-(Trimethylsilyl)propynamides

“…The presence of a trimethylsilyl group at the triple bond favors stabilization of carbofunctional acetylene derivatives and their adducts, deactivates the triple bond toward nucleophiles [9], and ensures regioselective cycloaddition of azides at the triple of bond of various trimethylsilylalkynes with formation of the corresponding 4-trimethylsilyl-1H-1,2,3-triazoles [3,10] and cycloaddition of norbornadiene to the Co 2 (CO) 8 complex with (trimethylsilylpropynoyl)oxazolidine or sultam according to the Pauson-Khand reaction [5].…”