A highly efficient enantio- and diastereoselective synthesis of chiral cis-β-N-alkyl/arylamino cyclic alcohols has been realized by asymmetric hydrogenation of racemic α-amino cyclic ketones via DKR catalyzed by [RuCl2((S)-Xyl-SDP)((R,R)-DPEN)]. The enantioselectivities of the reaction were up to 99.9% ee with 99:1 cis-selectivities. A practical catalytic asymmetric synthesis of all four isomers of
An expedient total synthesis of optically active piperidine and indolizidine alkaloids (−)-β-conhydrine and (−)-lentiginosine
作者:Ahmed Kamal、Saidi Reddy Vangala
DOI:10.1016/j.tet.2010.11.011
日期:2011.2
Attempts directed toward the stereocontroled total synthesis of piperidine and indolizidine alkaloids resulted in the synthesis of (−)-β-conhydrine 1 and (−)-lentiginosine 3. The synthesis of 1 and 3 were developed from protected d-mannitol as the chiral precursor, which involved nucleophilic addition and azide nucleophilic substitution, Barbier allylation, ring closing metathesis, and Sharpless asymmetric
Dipole-stabilized carbanions: the .alpha.' lithiation of piperidides
作者:Peter Beak、William J. Zajdel
DOI:10.1021/ja00316a033
日期:1984.2
On etudie les α'-lithiations et les substitutions electrophiles sur 2 series de piperidides
在 etudie les α'-lithiations et les 取代亲电体 sur 2 series de piperidides
Protecting-Group-Directed Regio- and Stereoselective Oxymercuration–Demercuration: Synthesis of Piperidine Alkaloids Containing 1,2- and 1,3-Amino Alcohol Units
efficient synthesis of naturallyoccurring 1,2- and 1,3-amino alcohol unit containing 2-substituted piperidine alkaloids and their analogues has been developed from l-pipecolinic acid. The protocol describes the regio- and stereoselective oxymercuration–demercuration of 2-alkenyl piperidines based on protecting groups to give piperidine alkaloids as a key step. An efficient synthesis of naturally occurring
carried out the stereoselectivesynthesis of (-)-β-conhydrine and (+)-α-conhydrine, two bioactive α-hydroxyalkyl-substituted piperidines, using the commercially available and inexpensive amino alcohol (S,S)-(+)-pseudoephedrine as chiralauxiliary. The key step of this synthesis relies on new methodology previously developed in our group, consisting of the chemo- and diastereoselective addition of Grignard