Highly Enantioselective and Regioselective Substitution of Morita–Baylis–Hillman Carbonates with Nitroalkanes

A highly enantioselective and regioselective substitution reaction of the Morita–Baylis–Hillman (MBH) carbonates with nitroalkanes catalyzed by a quinidine-derived tertiary amine–thiourea catalyst has been developed. The described method, which is different from most organocatalytic allylic substitutions of the MBH adducts to date, represents a novel approach to regioselectively functionalize the MBH adducts

Highly Enantioselective and Regioselective Substitution of Morita–Baylis–Hillman Carbonates with Nitroalkanes

A highly enantioselective and regioselective substitution reaction of the Morita–Baylis–Hillman (MBH) carbonates with nitroalkanes catalyzed by a quinidine-derived tertiary amine–thiourea catalyst has been developed. The described method, which is different from most organocatalytic allylic substitutions of the MBH adducts to date, represents a novel approach to regioselectively functionalize the MBH adducts

Asymmetric Allylic Alkylation of Isatin-Derived Morita–Baylis–Hillman Carbonates with Nitroalkanes

A stereoselective allylic alkylation of isatin-derived Morita–Baylis–Hillman (MBH) carbonates with nitroalkanes has been developed. In the presence of 10 mol % β-isocupreidine (β-ICD), 3,3′-disubstituted oxindoles were prepared with moderate diastereoselectivities and excellent enantioselectivities

Enantioselective Morita−Baylis−Hillman Reaction of Isatins with Acrylates: Facile Creation of 3-Hydroxy-2-oxindoles

The first tertiary amine catalyzed enantioselective Morita−Baylis−Hillman (MBH) reaction of isatins with acrylates has been demonstrated, allowing asymmetric synthesis of biologically significant 3-substituted-3-hydroxy-2-oxindoles in good yields and with excellent enantioselectivities. The C6′−OH group of β-isocupreidine (β-ICD) is believed to facilitate the key proton transfer step in the MBH reaction, via an intramolecular proton relay process

Enantioselective Morita−Baylis−Hillman Reaction of Isatins with Acrylates: Facile Creation of 3-Hydroxy-2-oxindoles

The first tertiary amine catalyzed enantioselective Morita−Baylis−Hillman (MBH) reaction of isatins with acrylates has been demonstrated, allowing asymmetric synthesis of biologically significant 3-substituted-3-hydroxy-2-oxindoles in good yields and with excellent enantioselectivities. The C6′−OH group of β-isocupreidine (β-ICD) is believed to facilitate the key proton transfer step in the MBH reaction, via an intramolecular proton relay process

Hydrogen-Bonding Directed Reversal of Enantioselectivity

A successful stereochemical reversal was achieved in AgOAc catalyzed [3+2] cycloaddition by the formation of hydrogen bonding between ligand and reactant. This strategy provides an efficient and convenient route to prepare both enantiomers of a chiral compound. DFT studies proposed a reasonable mechanism of the reversal of the enantioselectivity; hydrogen bonding changed the transition state. The strategy may provide some useful hints for ligand design

Highly Enantioselective Regiodivergent Allylic Alkylations of MBH Carbonates with Phthalides

Phthalides were used for the first time in the allylic alkylation reactions with MBH carbonates for the creation of chiral 3,3-disubstituted phthalides. Highly enantioselective regiodivergent synthesis of γ-selective or β-selective allylic alkylation products was achieved by employing bifunctional chiral phosphines or multifunctional tertiary amine–thioureas as the catalyst, respectively. It was demonstrated that proper selection of catalysts and reaction conditions would differentiate an S_N2′–S_N2′ pathway and an addition–elimination process, yielding different regioisomers of the allylic alkylation products in a highly enantiomerically pure form

Asymmetric Construction of Functionalized Bicyclic Imides via [3 + 2] Annulation of MBH Carbonates Catalyzed by Dipeptide-Based Phosphines

A highly enantioselective [3 + 2] annulation of MBH carbonates and maleimides catalyzed by chiral phosphines has been developed. In the presence of 5 mol % of l-Thr-l-Val-derived phosphine 6, functionalized bicyclic imides were prepared in excellent yields, and with high diastereoselectivities and nearly perfect enantioselectivities

Highly Enantioselective Regiodivergent Allylic Alkylations of MBH Carbonates with Phthalides

Phthalides were used for the first time in the allylic alkylation reactions with MBH carbonates for the creation of chiral 3,3-disubstituted phthalides. Highly enantioselective regiodivergent synthesis of γ-selective or β-selective allylic alkylation products was achieved by employing bifunctional chiral phosphines or multifunctional tertiary amine–thioureas as the catalyst, respectively. It was demonstrated that proper selection of catalysts and reaction conditions would differentiate an S_N2′–S_N2′ pathway and an addition–elimination process, yielding different regioisomers of the allylic alkylation products in a highly enantiomerically pure form

Highly Enantioselective Regiodivergent Allylic Alkylations of MBH Carbonates with Phthalides

Phthalides were used for the first time in the allylic alkylation reactions with MBH carbonates for the creation of chiral 3,3-disubstituted phthalides. Highly enantioselective regiodivergent synthesis of γ-selective or β-selective allylic alkylation products was achieved by employing bifunctional chiral phosphines or multifunctional tertiary amine–thioureas as the catalyst, respectively. It was demonstrated that proper selection of catalysts and reaction conditions would differentiate an S_N2′–S_N2′ pathway and an addition–elimination process, yielding different regioisomers of the allylic alkylation products in a highly enantiomerically pure form