Lewis acid-mediated synthesis of mono- and tris-indole adducts from chiral aziridines

Abstract

Lewis acid-mediated regio- and stereoselective nucleophilic addition of 2- (or) 3-substituted indoles to non-activated aziridine 2-carboxaldehydes in dioxane afforded 2-(indol-3-ylhydroxymethyl)aziridines whose ring openings with various nucleophiles rendered multi-substituted tryptamine derivatives....

α‐Aziridinyl Carbenium Ion Intermediate and Stereoselective Dehydroxylative Diarylation of Aziridin‐2‐yl Carboxaldehyde

“…of aziridine-2-yl carboxaldehyde we only speculated the possible intermediacy of α-aziridinyl carbenium ion without any direct evidence. [19] To explain the stereoselective Lewis-acid-mediated dehydroxylative cross-coupling reactions shown in all previous Schemes 3, 4 and 5, we propose carbenium ion intermediates 8 or 8-BF 3 , formed by the reaction between aziridinyl alcohol 3 a and BF 3 • OEt 2 (Figure 2). When aziridinyl alcohol 3 a was mixed with BF 3 • OEt 2 in CD 3 CN, a new olefinic signal at 5.79 ppm with a J value of 1.6 Hz was observed in the 1 H NMR spectra (Figure 2).…”

“…In our early study with the addition of three electron‐rich indoles to one equiv. of aziridine‐2‐yl carboxaldehyde we only speculated the possible intermediacy of α‐aziridinyl carbenium ion without any direct evidence [19] …”

Bis-indolylation of aldehydes and ketones using silica-supported FeCl3: molecular docking studies of bisindoles by targeting SARS-CoV-2 main protease binding sites

“…Consequently, several methods have been reported for the synthesis of these compounds. A variety of reagents such as protic acid, 28 Lewis acids, 29 transition and non-transitional metal salts, 30 solid acidic catalysts 31 and ionic liquids 32 have been employed to accomplish this transformation. However, many of these methods suffer from disadvantages such as unsatisfactory yields, expensive catalysts, long reaction times, toxic organic solvents, laborious work-up procedures, requirement of special apparatus, and harsh reaction conditions.…”