Conjugate additions to phenylglycinol-derived unsaturated delta-lactams. Enantioselective synthesis of uleine alkaloids.
The stereochemical outcome of the conjugate addition of a variety of stabilized nucleophiles (2-indoleacetic enolates and sulfur-stabilized anions) to the phenylglycinol-derived unsaturated lactams trans-2, cis-2, and its 8-ethyl-substituted analogue 10 is studied. The factors governing the exo or endo facial stereoselectivity are discussed. This methodology provides short synthetic routes to either cis- or trans-3,4-disubstituted enantiopure piperidines as well as efficient routes for the enantioselective construction of the tetracyclic ring system of uleine alkaloids, both in the normal and 20-epi series. The formal total synthesis of several alkaloids of this group is reported.
Amat
Mercedes
M
Laboratory of Organic Chemistry and Department of Physical Chemistry, Faculty of Pharmacy, University of Barcelona, 08028 Barcelona, Spain. amat@ub.edu
Pérez
Maria
M
Llor
Núria
N
Escolano
Carmen
C
Luque
F Javier
FJ
Molins
Elies
E
Bosch
Joan
J
D000470:Alkaloids / Q000138:chemical synthesis*; D001952:Bridged-Ring Compounds / Q000138:chemical synthesis*; D018360:Crystallography, X-Ray; D004983:Ethanolamines; D005998:Glycine / Q000031:analogs & derivatives* / Q000737:chemistry*; D007769:Lactams / Q000138:chemical synthesis*; D008968:Molecular Conformation; D013237:Stereoisomerism
D000470:Alkaloids; D001952:Bridged-Ring Compounds; D004983:Ethanolamines; D007769:Lactams; C428545:uleine; C005332:N-phenylethanolamine; D005998:Glycine