TiCl4/t-BuNH2-Promoted Hydroamination/Annulation of δ-Keto-acetylenes: Synthesis of Novel Pyrrolo[1,2-a]indol-2-carbaldehydes
摘要:
[GRAPHICS]An original TiCl4/t-BuNH2-mediated hydroamination/annulation domino reaction of delta-keto-acetylenes is described. The synthesis of pyrrolo[ 1,2-a] indole-2-carbaldehydes, starting from 2-carbonyl-1-propargyl-1H-indoles runs under mild reaction conditions. A conceivable mechanism is also discussed. TiCl4 has proved to be an effective multiactivity reagent: catalyst/Lewis acid/water scavenger. Some unpublished 2-carbonyl-1-propargyl- 1H-indoles are prepared by means of Suzuki- and Negishi-type reactions.
α-Hydroxydimethylacetal/ketal as an α-hydroxycarbonyl equivalent in interrupted Heyns/Amadori rearrangement: regioselective synthesis of substituted C2- and C3-acylindoles
作者:Minakshi Altia、Pazhamalai Anbarasan
DOI:10.1039/d4nj00771a
日期:——
intramolecular trapping of the aminoenol intermediate derived from o-acyl/formylanilines and α-hydroxydimethylacetals/ketals followed by rearrangement/aromatization in the presence of acid. Important features include the use of α-hydroxydimethylacetal/ketal as an α-hydroxycarbonyl equivalent, excellent regiocontrol, good functional group tolerance, selectivesynthesis of acylindoles, gram-scale synthesis, and