Catalytic asymmetric coupling of vinylogous species via deconjugated butenolide addition to vinylogous imines in situ generated from arylsulfonyl indoles

Abstract

An efficient catalytic asymmetric coupling of vinylogous species is developed via deconjugated butenolides addition to vinylogous imines in situ generated from arylsulfonyl indoles. With quinine-derived bifunctional squaramide as the catalyst,...

Asymmetric Addition of α-Diazomethylphosphonate to Alkylideneindolenine Catalyzed by a Trifunctional BINAP-Based Monophosphonium Salt

“…The wide spectrum of bioactivities of indole-containing compounds is often strongly associated with the functionalization at the C-3 position. Thus, impressive efforts have been made toward developing efficient methods for accessing 3- sec -alkyl-substituted indoles with various functional groups. − Among them, additions of various nucleophiles or pronucleophiles, such as nitroalkanes, ,, aldehydes, , 1,3-dicarbonyls, , electron-rich phenols, ,, thiols, and others, − , to vinylogous imines formed in situ from 3-(1-arylsulfonylalkyl)­indoles have been achieved, in particular the asymmetric version catalyzed by chiral tertiary amine thioureas, bis-amidine catalysts, and ammonium salts. ,− Despite this great progress, the substrates are mainly limited to 2-substituted sulfonyl indoles . For 2-unsubstituted sulfonyl indoles, only oxindolylideneindolenine and copper phosphoramidite complex-catalyzed addition of Grignard reagents to vinylogous imines have been shown to achieve good enantioselectivity.…”

Catalytic enantioselective hydrophosphinylation of in situ-generated indole-derived vinylogous imines to access 3-(1-diphenylphosphoryl-arylmethyl)indoles

“…However, almost all of the reported methods are restricted to attack at the vinylogous imine intermediates A by carbon nucleophiles using asymmetric organocatalysts or metal catalysts (Scheme 1a). 10 To the best of our knowledge, only one report on the asymmetric hydrothiolation of sulfonyl indoles, using a Cinchona alkaloid-derived thiourea catalyst for the synthesis of 3-alkylindole derivatives, has been documented by the group of Li and Liu (Scheme 1b). 11 Therefore, it is conceivable that there could be a great opportunity for research into the asymmetric hydrofunctionalization of indole-derived vinylogous imine intermediates A with heteroatom nucleophiles to access C3-functionalized indoles.…”