title: Efficient total synthesis of (+)-dihydropinidine, (-)-epidihydropinidine, and (-)-pinidinone.
abstract: The 2,6-disubstituted piperidine alkaloids (+)-dihydropinidine (1), (-)-epidihydropinidine (2) (as HCl salts), and (-)-pinidinone (3) were efficiently synthesized from (S)-epichlorohydrin (7) as common substrate using regioselective Wacker-Tsuji oxidation of alkenylazides 10 and 14 as well as a highly diastereoselective reduction of cyclic imine 11 as key steps. The protecting group free total syntheses represent the up to date shortest routes with highest overall yields for all three naturally occurring alkaloids (1-3). The first single-crystal X-ray analysis of (-)-epidihydropinidine hydrochloride (2·HCl) confirmed its proposed absolute configuration to be (2S,6S), corresponding to that of the isolated natural product.
authors.affiliation: Department of Organic Chemistry, Slovak University of Technology, Radlinského 9, SK-812 37 Bratislava, Slovakia.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Kavala
authors.forename: František
authors.initials: F
authors.lastname: Mathia
authors.forename: Jozef
authors.initials: J
authors.lastname: Kožíšek
authors.forename: Peter
authors.initials: P
authors.lastname: Szolcsányi
mesh_terms: D000470:Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D028222:Picea / Q000737:chemistry; D028223:Pinus / Q000737:chemistry; D010880:Piperidines / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000470:Alkaloids; D010880:Piperidines; C409726:dihydropinidine; C559181:epidihydropinidine; C559182:pinidinone