An efficient method for intermolecular N-arylation of oxazolidinones using Pd(2)dba(3) and various phosphine ligands in the presence of a weak base is reported. The conditions allow the use of cheaper aryl chlorides containing functionalities such as enolizable ketones, amides, etc., which would be incompatible with other coupling methods. The coupling reaction can be used to prepare enantiopure N-aryl beta-amino alcohols. Depending on the stereoelectronic nature of the aryl chloride, careful choice of ligand was necessary for the success of these reactions. [reaction: see text]
[reaction: see text] The acid-mediated Prins/pinacol and the triple domino reactions Diels-Alder/Prins/pinacol were used to construct highly functionalized bicyclo[m.n.1]alkanones 19-29 and 33a-c possessing various ring sizes from ketals 8-18 and 31a-c in 44-96% yields. This approach proves to be highly efficient and reliable to generate high molecular complexity in a single step.
Lewis-base-catalyzed cycloisomerization of bis(enones) to decalins has been demonstrated as an alternative to the traditional Lewis acid catalyzed Diels-Alder cycloaddition. In this process, a trialkylphosphine mediates both bond formation steps in two distinct catalytic cycles. The single-pot operation generates two carbon-carbon bonds and up to five contiguous stereocenters in one step, starting from achiral, aliphatic substrates; eight examples are provided. [reaction: see text]
This account depicts strategies adopted during the development of the ?-opioid receptor agonist CJ-15,161. While the original discovery synthesis was enabled for scale-up, concomitant process research aimed at identifying a novel and more efficient route was undertaken. In the
former case, an efficient four-step sequence has been developed, where the process features four consecutive regioselective and stereospecific inversions at a single aziridinium stereogenic center, which leads to overall retention of stereochemistry in a single operation. The search for novel
routes has also resulted in two converging methods involving efficient intermolecular N-arylation strategies. The first approach involves Pd-catalyzed intermolecular N-arylation of an appropriately functionalized diamine, obtained from the precursor ?-amino acids or, more conveniently,
from the corresponding 1,2-amino alcohols. The second approach exploits efficient intermolecular N-arylation of oxazolidinones using catalytic copper in the presence of a bidentate ligand leading to a straightforward and practical synthesis of cJ-15,161.
An efficient enantioselective synthesis of (+)-isofregenedol was achieved in 13 steps from commercially available cyclohexene oxide without the use of protecting groups. The tetrahydronaphthalenic core of isofregenedol was obtained via a gold(I)-catalyzed benzannulation recently developed in our laboratory.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.