First Propargyl Azides Bearing Strong Acceptor Substituents and Their Effective Conversion into Allenyl Azides: Influence of the Electronic Effects of Substituents on the Reactivity of Propargyl Azides

Abstract

We have succeeded in the synthesis of propargyl azides containing 1-or 3-phenylthio functionalities. The selective oxidation of their sulfur atoms to sulfoxides and sulfones allows access to the first propargyl azides bearing acceptor substituents. Interestingly, the prototropic rearrangement of the latter propargyl azides leads to the formation of allenyl azides with relatively high stabilities and with moderate to good yields. Propargyl azides containing phenylthio functionalities react in the presence of nucleophiles to afford the expected N-un-

Theoretical investigation of Banert cascade reaction

“…The intermediate IM-A2 further rearranges to propargyl azide IM-A3. This propargyl azide is the key intermediate for the Banert cascade reaction [ 44 ]. Montagnat et al [ 45 ] also synthesized and isolated structurally diverse propargyl azides from aldehydes and alkynes, which also support existence of this key intermediate in Banert cascade reaction ( scheme 3 ).…”

Synthesis of N-unsubstituted 1,2,3-triazoles via a cascade including propargyl azides, allenyl azides, and triazafulvenes

“…On the other hand, such properties are highly welcome when NH-1,2,3-triazoles were synthesized as biologically active agents by the cascade method. [32][33][34][35][36][38][39][40][41][42]45 …”

“…Thus, the methods have already been applied to prepare some N-unsubstituted 1,2,3-triazoles. [32][33][34][35][36][37][38][39][40][41][42][43][44][45] Our previous studies were focused on the mechanisms to explain the formation of these heterocycles. [28][29][30][31] …”

Guanidines in Organic Synthesis

“…For the preparation of acceptor-substituted propargyl azide through substitution of the propargyl precursors bearing a leaving group, the reaction of halide with TMGA (28) resulted in the vinyl azide instead of a desired azide, because the presence of the acceptor substituent causes prototropic isomerization under basic conditions [111]. Expected displacement was observed when sulfur containing propargyl azide was subjected to the reaction, and the following oxidation with m-chloroperbenzoic acid (mCPBA) gave the sulfonyl substituted propargyl azide even in low yield (Scheme 4.45).…”