92011-93-3Relevant articles and documents
Pd-catalyzed asymmetric allylic amination with BOP ligands and its applications to the synthesis of fused polycyclic alkaloids
Zang, Yang,Ojima, Iwao
supporting information, p. 3288 - 3292 (2015/05/27)
Abstract Pd-catalyzed asymmetric allylic amination reaction of piperonylamides and a 2-siloxymethylcyclohexenyl carbonate, using chiral biphenol-based diphosphinite (BOP) ligands gave the corresponding cyclohexenylpiperonylamides in excellent yield and en
Synthesis of chiral biphenol-based diphosphonite ligands and their application in palladium-catalyzed intermolecular asymmetric allylic amination reactions
Shi, Ce,Chien, Chih-Wei,Ojima, Iwao
, p. 674 - 680 (2011/10/12)
A library of new 2,2'-bis(diphenylphosphinoyloxy)-1,1'-binaphthyl (binapo)-type chiral diphosphonite ligands was designed and synthesized based on chiral 3,3',5,5',6,6'-hexasubstituted biphenols. These bop ligands have exhibited excellent efficiency in a palladium-catalyzed intermolecular allylic amination reaction, which provides a key intermediate for the total synthesis of Strychnos indole alkaloids with enantiopurities of up to 96% ee. A library of chiral diphosphonite (bop) ligands was synthesized based on chiral hexasubstituted biphenols with fine-tuning capability. Their application for the synthesis of a key intermediate to indole alkaloids through a palladium-catalyzed intermolecular asymmetric allylic amination is reported (TBS=tert-butyldimethylsilyl, TIPS=triisopropylsilyl, dba=dibenzylideneacetone). Copyright
Divergent enantioselective synthesis of (-)-galanthamine and (-)-morphine
Trost, Barry M.,Tang, Weiping,Toste, F. Dean
, p. 14785 - 14803 (2007/10/03)
An efficient divergent synthetic strategy for the synthesis of the opiate and amaryllidaceae alkaloids emerges by employing a Pd-catalyzed asymmetric allylic alkylation (AAA) to set the stereochemistry. Three generations of syntheses of galanthamine are discussed in detail with particular focus on the scope of the palladium-catalyzed AAA reactions and intramolecular Heck reactions. The pivotal tricyclic intermediate is available in six steps from 2-bromovanillin and the monoester of methyl 6-hydroxycyclohexene-1-carboxylate. This intermediate requires only two steps to convert to (-)-galanthamine. Using a Heck vinylation, we found that the fourth ring of codeine/morphine could be formed. The final ring formation involves a novel visible light-promoted hydroamination. Thus, six steps are required to convert the pivotal tricyclic intermediate into codeine, which has been demethylated in high yield to morphine.