18881-13-5Relevant articles and documents
A general strategy for the catalytic, highly enantio- and diastereoselective synthesis of indolizidine-based alkaloids
Abels, Falko,Lindemann, Chris,Schneider, Christoph
supporting information, p. 1964 - 1979 (2014/03/21)
Sixteen indolizidine-based alkaloids (IBAs) that were isolated as poison constituents of the skin of frogs were synthesized in a highly flexible and stereoselective manner. As a key step, a three-component, organocatalytic, highly enantio- and diastereose
Regioselective and stereoselective copper(I)-Promoted allylation and conjugate addition of N -Boc-2-lithiopyrrolidine and N -Boc-2-lithiopiperidine
Coldham, Iain,Leonori, Daniele
experimental part, p. 4069 - 4077 (2010/08/20)
Copper salts have been screened for transmetalation and electrophilic quench of N-tert-butoxycarbonyl-2-lithiopyrrolidine (N-Boc-2-lithiopyrrolidine) and N-Boc-2-lithiopiperidine, formed by deprotonation of N-Boc-pyrrolidine and N-Boc-piperidine, respectively. Transmetalation with zinc chloride then (lithium chloride solubilized) copper cyanide followed by allylation typically gives mixtures of regioisomers (SN2 and SN2′ products), whereas transmetalation with copper iodideTMEDA then allylation occurs regioselectively (SN2 mechanism). Addition to an enone or α,β-unsaturated ester occurs by 1,4-addition. Asymmetric deprotonation of N-Boc-pyrrolidine or dynamic resolution in the presence of a chiral ligand of N-Boc-2-lithiopiperidine followed by the zinc/copper chemistry was successful and gave the allylated pyrrolidine and piperidine products with good enantioselectivity, although use of the copper iodide chemistry resulted in some loss of enantiopurity. The chemistry provides formal syntheses of (+)-allosedridine, (+)-lasubine II, and (+)-pseudohygroline and has been used for the synthesis of (+)-coniine, (-)-pelletierine, (+)-coniceine, (-)-norhygrine, and the ant extract alkaloids cis- and trans-2-butyl-5- propylpyrrolidine.
Convenient in situ synthesis of nonracemic N-protected β-amino aldehydes from β-amino acids. Applications in Wittig reactions and heterocycle synthesis
Davies, Simon B.,McKervey, M. Anthony
, p. 1229 - 1232 (2007/10/03)
N-Z-γ-amino alcohols derived from nonracemic β-amino acids are smoothly oxidised by manganese dioxide in acetonitrile to afford aldehydes which can be trapped in situ in Wittig reactions with carbonyl-substituted phosphoranes. The application of this methodology to the synthesis of the alkaloids (S)-(+)-N-BOC-coniine, (S)-(-)-coniceine and a pipecoline precursor is described.
