Acid-catalyzed ring-expansion of 4-(1-hydroxycyclobutyl)-1,2,3-triazoles

Abstract

We here reported a direct ring-opening/semipinacol rearrangement reaction of 4-(1-hydroxycyclobutyl)-1,2,3-triazole, in which N-acyl substituted 1,2,3-triazole was generated in situ and would trigger thermodynamically controlled electrocyclization ring-opening to afford rearrangement precursor...

One-pot synthesis of 4-substituted 2-fluoroalkyloxazoles from NH-1,2,3-triazoles and fluoroalkylated acid anhydrides

“…23 Very recently, first examples of NH-triazole ring cleavage with acylating agents via the intermediary of N -acyltriazoles were reported by us 24 and Li's group. 25 We have studied the cleavage of NH-triazoles in the presence of excess of fluorinated acid anhydride, which resulted in oxazole formation in the case of 4,5-disubstituted NH-triazoles. 24 However, this oxazole synthesis was not applicable to monosubstituted triazoles, and electron-deficient substituents on the aryl ring were not well tolerated.…”

Synthesis of N-vinyl isothiocyanates and carbamates by the cleavage of NH-1,2,3-triazoles with one-carbon electrophiles

“…Only very recently, NH-1,2,3-triazoles were successfully used in ring transformations, which was made possible by N -acylation followed by in situ cleavage of unstable N -acyltriazoles. 11,12 Cleavage of NH-1,2,3-triazoles with acyl halides led to β-haloenamides, 11 while reactions with fluoroalkylated acid anhydrides provides routes to fluoroalkylated oxazoles or 2-acylaminoketones (Scheme 1). 12 Thus, utilization of NH-1,2,3-triazoles as building blocks is a highly promising area in organic chemistry.…”

NH-1,2,3-triazoles as versatile building blocks in denitrogenative transformations

“…Their cleavage with acyl chlorides 10 catalysed by triflic acid provided efficient access to cyclic enaminones 29 (Scheme 18). 22 The reaction proceeded via the cleavage of N -acyltriazole and semipinacol rearrangement cascade. The procedure was found to be easily scalable to give multifunctional substrates in good yields.…”