Enantioselective transformations
of olefins are among the most
important strategies for the asymmetric synthesis of organic compounds.
Chemo-, diastereo-, and stereoselective control of reactions with
internal acyclic alkenes for the construction of functionalized acyclic
alkanes still remain a persistent challenge. Here, we report a palladium-catalyzed
asymmetric regiodivergent Heck-type diarylation of internal acyclic
alkenes. The 1,2-diarylation of two accessible acyclic alkenes, cinnamyl
carbamates and enamides with diazonium salts and aromatic boronic
acids, furnishes products containing vicinal stereogenic centers via
the stereospecific formation of carbonyl coordination-assisted transient
palladacycles. Moreover, the asymmetric migratory diarylation of enamides
enables the formation of incontiguous stereocenters by an interrupted
diastereoselective 1,3-chain-walking process. This protocol streamlines
access to highly functionalized multisubstituted enantioenriched carbamates
and amine derivatives which are embedded in the key biologically active
motifs.
Nitrogen-based heterocycles have aroused widespread interest due to their reoccurrence in many pharmaceuticals. Amongst these motifs, the enantioenriched lactams are the ubiquitous scaffolds found in myriad biologically active natural products and drugs. Recently, the transition metal-catalyzed asymmetric carbamoylation has been widely employed as a straightforward arsenal for chiral lactam architecture synthesis, including β-lactam and γ-lactam. However, despite the extensive efforts, there still remains no protocol to accomplish the related δ-lactam synthesis. In this manuscript, the Ni-catalyzed enantioselective carbamoylation of unactivated alkenes by the leverage of reductive dicarbofunctionalization strategy allows for the expedient access to two types of mostly common six-membered lactams: 3,4-dihydroquinolinones and 2-piperidinone in high yield and enantioselectivity. This protocol features with good functional group tolerance, as well as broad substrate scope. The newly developed chiral 8-Quinox skeleton ligand is the key parameter for this transformation, which significantly enhances the reactivity and enantioselectivity.
The construction of vicinal stereogenic centers via the simultaneous formation of two C-C bonds across alkenes under oxidative conditions is a stubborn challenge. Herein, we report a Pd(II)-catalyzed highly enantioselective...
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