1,6-Addition of 1,2,3-NH triazoles topara-quinone methides: Facile access to highly selective N¹and N²substituted triazoles

Abstract

Regioselective syntheses of N1 and N2 substituted triazoles via 1,6-addition of 1,2,3-NH triazole with p-QM were developed under mild reaction conditions. Isomerization of N1 to N2 substituted triazoles was also achieved in the presence of AlCl3.

Addition of sulfonylphthalides to para-quinone methides: Selective 1,6-additions and oxidative annulations

“…9 Recently, we have also developed the reagent controlled regioselective addition of 1,2,3-triazoles to p -QMs for the synthesis of N 1 and N 2 substituted triazoles. 10 Unexpectedly, very limited attention has been paid to the reaction of SP with p -QMs so far. Prof.…”

Solvent-controlled regioselective C(5)–H/N(1)–H bond alkylations of indolines and C(6)–H bond alkylations of 1,2,3,4-tetrahydroquinolines with para-quinone methides

“…17,18 Thus far, by attacking various nucleophiles such as pyrroles, indoles, naphthols, aldehydes, azaalkylarenes, imidazopyridines, and 1,2,3-NH triazoles in the terminal carbon–carbon exocyclic double bond, p -QMs generated 1,6-addition products. 19 Yao and Lin's group reported a single example of unsymmetrical triarylmethanes through a 1,6-addition arylation reaction of p -QM with N -methylindoline and N -methyltetrahydroquinoline under metal-free conditions. 20 At this point, it is important to note that Zhang and Rong's group simultaneously reported the construction of the C–N bond from the 1,6-conjugate addition reaction of p -QMs and substituted 1,2,3,4-tetrahydroisoquinolines or indolines under catalyst-free and room temperature conditions.…”

HBF4‐Catalyzed 3,6‐Bis‐diarylmethylation of Carbazoles withpara‐Quinone Methides

“…The C‐alkylation of many N ‐heterocycles such as pyrroles/indoles, [17] imidazopyridines, [18] 2‐alkylazaarenes, [19] 8‐aminoquinolines, [20] indoline/tetrahydroisoquinolines [21] and other electron rich aromatic compounds [22] with p ‐QMs, through 1,6‐conjugate addition reactions, have been well explored. In addition, the regioselective N ‐alkylation of 1,2,3‐NH triazoles has been achieved through a 1,6‐conjugate addition to p ‐QMs [23] . In 2017, Sun and coworkers have demonstrated the in situ formed aza‐ para ‐quinone methides as alkylating reagents for asymmetric N ‐alkylation of indoles and carbazoles [24] .…”

“…In addition, the regioselective N-alkylation of 1,2,3-NH triazoles has been achieved through a 1,6-conjugate addition to p-QMs. [23] In 2017, Sun and coworkers have demonstrated the in situ formed azapara-quinone methides as alkylating reagents for asymmetric Nalkylation of indoles and carbazoles. [24] Later, Samanta and coworkers described p-QMs as N-alkylating agent for Ndiarylmethylation of unprotected carbazoles using Zn(OTf) 2 via 1,6-Aza-Michael addition.…”