2- Substituted 1,2,3-triazole 1-oxides silylation

Substituted (5R,6A,)-6-(dimethyl(phenyl)silyl)-2-phenyldihydropyrazolo[l,2- ][l,2,4]triazole-l,3(2//,5//)-dione 716, synthesized via the [3+2] annulation of a-substituted allylic silanes 715 with PTAD, were oxidized to the corresponding hydroxy substituted urazoles 717. This work shows that allylsilanes with a single substituent at the allylic carbon undergo exclusive stereoselective [3+2] annulation (Scheme 114) <2007TL6671>. 

Substituted 1,2,3-triazole 1-oxides 326 are silylated at the oxygen atom to give moisture sensitive silyloxytriazolium salts, which have been characterized by their NMR spectra (1993JCS(P1)625, 1992JCS(P1)2555). 

Davies et al. disclosed a one-pot indole synthesis from cyclohexene 154 and tosylazide (155).The reaction proceeds via a click reaction to form the triazole, followed by Rh-based decomposition, pyrrole formation, and oxidation to indole 156. The indoles (and azaindoles) are formed in very good yield and may be substituted with alkyl-, aryl-, or silyl-proteaed alcohols (13JA11712). 

P-D-Rihofuranosyl derivatives of various 1,2.4-triazoles have been reported, along with P-D-arabinofurano l and 2 - and 5 -deo3 - analogues. Ribofuranosylation of 1.2,3-triazoIe (4) gave the 2- substituted nucleoside, while the l,4-thlazin-3-one nucleoside (5), and its S-oxide, a potential tetrahedral intermediate analogue for enzymes in pyrimidine nucleoside metabolism, have been prepared by silyl-Hilbert-Johnson methods, Also available by standard methods are P-D-ribofuranosyl derivatives of... 

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