15191-27-2Relevant academic research and scientific papers
Synthesis of (-)-Cytisine Using a 6- endo aza-Michael Addition
Barát, Viktor,Csókás, Dániel,Bates, Roderick W.
, p. 9088 - 9095 (2018/07/25)
An asymmetric synthesis of (-)-cytisine has been achieved. The piperidine C-ring was formed using a stereodivergent intramolecular 6-endo aza-Michael addition. The B-ring was established by intramolecular pyridine N-alkylation. The absolute stereochemistry was established by an Evans acyl oxazolidinone enolate alkylation reaction that proceeded with an unexpected stereochemical outcome due to participation of the pyridine nitrogen lone pair.
Ligand-controlled regiodivergent nickel-catalyzed annulation of pyridones
Donets, Pavel A.,Cramer, Nicolai
, p. 633 - 637 (2015/03/04)
The 1,6-annulated 2-pyridone motif is found in many biologically active compounds and its close relation to the indolizidine and quinolizidine alkaloid core makes it an attractive building block. A nickel-catalyzed C-H functionalization of 2-pyridones and subsequent cyclization affords 1,6-annulated 2-pyridones by selective intramolecular olefin hydroarylation. The switch between the exo- and endocyclization modes is controlled by two complementary sets of ligands. Irrespective of the ring size, the regioselectivity during the cyclization is under full catalyst control. Simple cyclooctadiene promotes an exo-selective cyclization, whereas a bulky N-heterocyclic carbene ligand results in an endoselective mode. The method was further applied in the synthesis of the lupin alkaloid cytisine.
Concise synthesis of (±)-cytisine via lithiation of N-Boc-bispidine
Stead, Darren,O'Brien, Peter,Sanderson, Adam J.
, p. 4459 - 4462 (2007/10/03)
(Chemical Equation Presented) (±)-Cytisine has been synthesized in 19% overall yield via a six-step approach from commercially available materials. Key features of this new strategy are as follows: (i) initial construction of the bispidine core, (ii) lithiation-transmetalation-allylation of an N-Boc-bispidine, and (iii) a Pd/C-mediated dihydropyridone oxidation-N- debenzylation process.
Total synthesis of (±)-cytisine
O'Neill, Brian T.,Yohannes, Daniel,Bundesmann, Mark W.,Arnold, Eric P.
, p. 4201 - 4204 (2007/10/03)
(equation presented) The nicotine partial agonist cytisine was prepared in five steps featuring an "in situ" Stille or Suzuki biaryl pyridine coupling. Differentiation of the pyridyl rings was accomplished via selective benzylation and then reduction of a pyridinium ring. The penultimate diazabicyclo[3.3.1]-nonane intermediate was obtained with high diastereoselectivity. A similar sequence has been employed for the synthesis of novel derivative 9-methoxycytisine.
Total synthesis of (+/-)-cytisine via the intramolecular heck cyclization of activated N-alkyl glutarimides.
Coe
, p. 4205 - 4208 (2007/10/03)
[reaction:see text] A synthesis of racemic cytisine 1 has been developed utilizing an intramolecular Heck cyclization to prepare the bridged tricyclic intermediate 2. The cyclization employs activated glutarimide-derived ketene aminals 3 (X = P(O)OEt(2) or SO(2)CF(3)) and represents the first use of such intermediates in metal-catalyzed processes.
THERMAL DECOMPOSITION OF 2-HYDROXYBENZYLAMINES
Vinogradova, V. I.,Yunusov, M. S.
, p. 308 - 311 (2007/10/02)
The results are given of the preparation of a number of 2-hydroxybenzylamines and their thermal decomposition.The thermolysis reactions and the formation of the corresponding amines take place smoothly and with good yields.
