Use of azalactones in a “Pictet-Spengler-like” reaction. Stereoselective synthesis of 1,3,4-substituted tetrahydro-β-carbolines
作者:Jesús Ezquerra、Carlos Lamas、Alfredo Pastor、Pilar Alvarez、Juan José Vaquero、Will G Prowse
DOI:10.1016/0040-4039(96)01233-6
日期:1996.8
A “Pictet-Spengler-like” reaction between azalactones 1 and conformationally constrained tryptamines 4 in refluxing 1N HCl over 72 h. gave the corresponding tetrahydro-β-carbolines 3 in moderate to good yields. The observed equatorial orientation of the C-1 substituent in the THBC's results from a combination of the thermal reaction conditions and conformational constraints imposed by the starting
Stereoselective synthesis of 1,3,4-substituted tetrahydro-β-carbolines from indoles based on selective transformations
作者:Jesús Ezquerra、Concepción Pedregal、Carlos Lamas、Alfredo Pastor、Pilar Alvarez、Juan José Vaquero
DOI:10.1016/s0040-4020(97)00489-4
日期:1997.6
nucleophilic aziridine ring opening with a lower order indolyl magnesium cuprate obtaining the α,β-substituted tryptamines 5 and secondly, a “Pictet-Spengler-like” reaction between azalactones 12 and tryptamines 5. Under the acidic reaction conditions used, the thermodynamically favoured tetrahydro β-carbolines 4 are obtained due to the conformational restrictions imposed by the tryptamine substituents
Conformationally constrained serotonin analogues: Stereoselective synthesis of trans-3-(2-aminocycloalkyl)indoles by aziridine ring opening
作者:Jesús Ezquerra、Concepción Pedregal、Carlos Lamas、Alfredo Pastor、Pilar Alvarez、Juan José Vaquero
DOI:10.1016/0040-4039(95)02242-2
日期:1996.1
Trans-3-(2-aminocyclopentyl)indoles9a,c and trans-3-(2-aminocyclohexyl)indoles9b,d have been stereoselectively prepared by nucleophilic ringopening reaction of N-Boc cycloalkylaziridines 6a,b and the “lower order” magnesium cuprate II, generated from the corresponding indolilmagnesium bromides derived from 7a,b.
Cationic palladium and nickel complexes have been found to catalyze the ring-opening of meso-N-aryl aziridines with anilines very efficiently and furnish valuable 1,2-diamines in typically excellent yields. The active catalysts were generated in situ from the corresponding metal dichloride bis(triphenylphosphine) complexes through chloride abstraction with a silver salt. This new protocol is applicable across a broad substrate range with both cyclic as well as acyclic aziridines. In addition, cationic gold-phosphine complexes proved to be highly reactive as well as delivering products in comparable rates and yields.
Metal- and Additive-Free Intermolecular Aziridination of Olefins Using N-Boc-O-tosylhydroxylamine
作者:Jawahar L. Jat、Bhoopendra Tiwari、Dinesh Chandra、Puneet Kumar、Vikram Singh
DOI:10.1055/a-1879-7974
日期:2022.10
A metal and additive-free stereospecific direct N-H and N-Me aziridination of inactivated olefins is disclosed using N-Boc-O-tosylhydroxylamine (TsONHBoc) as an aminating agent in hexafluoroisopropanol (HFIP). The use of TsONHBoc, which generates the free aminating agent in situ under the reaction conditions, has several inherent advantages over other similar agents, such as low cost, easy access