4-Sulfanyl-substituted
1,2,3-triazoles were provided regioselectively
with good yields and broad scope via consecutive t-BuOK-promoted dephosphinylation of 1-phosphinyl-2-sulfanylethynes
and copper-catalyzed azide–alkyne cycloadditions (CuAAC) with
alkyl azides. Unsymmetrically substituted ditriazoles were successfully
obtained using a tandem dephosphinylative CuAAC protocol with diazides.
Direct CuAAC of the 1-phosphinyl-2-sulfanylethynes with azides afforded
regioisomeric mixtures of 4-phosphinyl-5-sulfanyl- and 5-phosphinyl-4-sulfanyl-1,2,3-triazoles
that were easily separable from one another. When the phosphinyl-
and sulfanyl-substituted triazoles were treated with t-BuOK, the dephosphination proceeded smoothly, yielding the corresponding
5- and 4-sulfanyltriazoles, respectively. 5-(1-Aryl-1-hydroxymethyl)-4-sulfanyltriazoles
were synthesized by stepwise treatment of 5-phosphinyl-4-sulfanyltriazole
with MeMgBr and arylaldehydes. Additionally, Ph2P(O) and
RS groups in the triazoles were easily converted to Ph2P and RSO2 by PhSiH3-reduction and m-CPBA-oxidation, respectively. Following the dephosphinylative
CuAAC of 1-phosphinyl-2-(4-t-butylphenylsulfanyl)ethyne
with aryl azides and m-CPBA-oxidation, potent antagonists
of pregnane X receptor LC-58 and LC-59 were
successfully produced.
Phosphanylnaphtho[2,1-d]oxazoles were synthesized successfully through one-pot phosphonation of naphthoquinone with diaryl(alkyl)phosphine oxides and Cu-catalyzed oxidative condensation with imines, followed by methylation and reduction. By applying 4-phosphorylnaphth[2,1-d]oxazole as a P, N-chelating...
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