Free radical-mediated aryl amination: a practical synthesis of (R)- and (S)-7-azaindoline 伪-amino acid was written by Srinivasan, Jayasree M.;Burks, Heather E.;Smith, Colin R.;Viswanathan, Rajesh;Johnston, Jeffrey N.. And the article was included in Synthesis in 2005.Electric Literature of C37H37BrN2O This article mentions the following:
Two nonnatural proline derivatives, (S)- and (R)-7-azaindoline 伪-amino acids I, have been prepared and isolated as their trifluoroacetate salts on gram scale. The convergent sequence (6 steps from 2-bromopyridine) employs phase transfer-catalyzed asym. alkylation of Ph2C:NCH2CO2Bu-t with 3-bromomethyl-2-bromopyridine to give (S)- and (R)-2-[N-(diphenylmethylene)amino]-3-(2-bromo-3-pyridyl)propanoates II, followed by their free radical-mediated aryl amination leading to cyclization. Implementation of the solid-liquid phase transfer conditions requires manual pulverization of CsOH, efficient mech. stirring, and effective low temperature control. This large scale free radical cyclization protocol replaces benzene solvent with toluene without complication, and the crystalline nature of the intermediates and final product enables straightforward purification at each stage, including enantiomeric enrichment. In the experiment, the researchers used many compounds, for example, (1S,2S,4S,5R)-2-((R)-(Allyloxy)(quinolin-4-yl)methyl)-1-(anthracen-9-ylmethyl)-5-vinylquinuclidin-1-ium bromide (cas: 200132-54-3Electric Literature of C37H37BrN2O).
(1S,2S,4S,5R)-2-((R)-(Allyloxy)(quinolin-4-yl)methyl)-1-(anthracen-9-ylmethyl)-5-vinylquinuclidin-1-ium bromide (cas: 200132-54-3) belongs to quinuclidine derivatives. Quinuclidine acts as a catalyst, a chemical building block and is used in organic synthesis. It is employed to prepare quinine and alkaloids. Carbamoyl boranes are generally prepared as adducts with tertiary amines, such as trialkyl amines, pyridine, or quinuclidine, via two synthetic approaches based either on amidation of amine-carboxyborane adducts or on hydrolysis of amine-cyanoboranes.Electric Literature of C37H37BrN2O
Referemce:
Quinuclidine – Wikipedia,
Quinuclidine | C7H13N | ChemSpider