95092-07-2Relevant academic research and scientific papers
Construction of azacycles by intramolecular amination of organoboronates and organobis(boronates)
Xu, Peilin,Zhang, Mingkai,Ingoglia, Bryan,Allais, Christophe,Dechert-Schmitt, Anne-Marie R.,Singer, Robert A.,Morken, James P.
supporting information, p. 3379 - 3383 (2021/05/10)
Intramolecular amination of organoboronates occurs with a 1,2-metalate shift of an aminoboron ate complex to form azetidines, pyrrolidines, and piperidines. Bis(boronates) undergo site-selective amination to form boronate-containing azacycles. Enantiomerically enriched azacycles are formed with high stereospecificity.
Microwave-assisted syntheses of N-heterocycles using alkenone-, alkynone- and aryl-carbonyl O-phenyl oximes: Formal synthesis of neocryptolepine
Portela-Cubillo, Fernando,Scott, Jackie S.,Walton, John C.
, p. 5558 - 5565 (2008/12/20)
(Chemical Equation Presented) This research aimed to provide a new and "clean" synthetic method that would enable both known and novel N-heterocycles to be prepared efficiently. O-Phenyl oximes were found to be excellent precursors for iminyl radicals with a variety of acceptor side chains. Dihyropyrroles were made in good yields from O-phenyl oximes containing pent-4-ene acceptors. The analogous process with a hex-5-enyl acceptor did not yield a dihydropyridine, probably because the 6-exo-trig ring closure of the iminyl radical was too slow to compete with H-atom abstraction. The iminyl radical from a precursor with a pent-4-yne type side chain underwent ring closure followed by rearrangement to afford a pyrrole derivative. Suitably substituted iminyl radicals ring closed readily onto aromatic acceptors, thus enabling several polycyclic systems to be accessed. Quinolines were made from 3-phenylpropanones via their O-phenyl oximes. Syntheses of phenanthridines starting from 2-formylbiphenyls were particularly efficient, and this approach enabled the natural product trisphaeridine to be made. Starting from 2-phenylnicotinaldehyde derivatives, ring closures of the derived iminyl radicals onto the phenyl rings yielded benzo[h][1,6]naphthyridines. Similarly, ring closure onto a phenyl ring from a benzothiophene-based iminyl yielded a benzo[b-]thieno[2,3-c]quinoline. By way of contrast, iminyl radical ring closure onto pyridine rings was not observed. However, iminyl radicals did cyclize onto indoles, enabling indolopyridines to be prepared. The latter route was exploited in a short formal synthesis of neocryptolepine starting from 2-((1H-indol-3-yl)methyl)cyclohexanone.
N-hydroxypyridine-2-thione carbamates. V. Syntheses of alkaloid skeletons by aminium cation radical cyclizations
Newcomb, Martin,Marquardt, Donald J.,Deeb, Thomas M.
, p. 2329 - 2344 (2007/10/02)
The title radical precursors (PTOC carbamates) were employed as sources of a variety of 5,6-unsaturated aminium cation radicals. 5-Exo radical cyclization followed by trapping by t-BuSH or the PTOC carbamate gave a variety of aklaloid skeletons, typically in good to excellent yields, including pyrrolidines, perhydroindoles, pyrrolizidines, tropanes, 9-azabicyclo[4.2.1]nonanes, 6-azabicyclo [3.2.1]octanes. 6-Exo and 7-endo cyclizations competed in a 6,7-unsaturated system.
A NOVEL THREE CARBON-AMINO GRIGNARD REAGENT: ITS USE IN AN EFFICIENT PYRROLIDINE SYNTHESIS
Basha, Fatima Z.,DeBernardis, John F.
, p. 5271 - 5274 (2007/10/02)
A novel primary amino protected Grignard reagent has been developed; 2,2,5,5-tetramethyl-1-aza-2,5-disilacyclopentane-1-propyl magnesium bromide 1a.Its usefulness is illustrated in the synthesis of 2-substituted pyrrolidines.
