α,α-Dicyanoolefins have emerged as versatile reactants, finding use as vinylogous nucleophiles, Michael acceptors and dienophiles in a variety of organic reactions. In the last few years, the reactivity of α,α-dicyanoolefins has been explored in various asymmetric transformations catalyzed by organocatalysts. In this review, we are presenting the recent advances in asymmetric organocatalytic transformations involving α,α-dicyanoolefins.

•DFT calculation using CAM-B3LYP functional were carried out to quantify nonlinear response of TPB derivatives.•NLO properties of TPB derivatives containing non-metal donor groups display linear relation with increased electron density.•In case of TPB derivatives containing metal donor complexes the NLO properties increases with increase in dipole moment.•Hyperpolarizability displays inverse relation with energy of highest occupied molecular orbital of the studied systems.Theoretical descriptions of the molecular nonlinear optical properties of triphenyl borazine (TPB) derivatives are presented by using DFT level theory on employing CAM-B3LYP functional. Based on computational calculation the extent of nonlinear response was account in terms of dipole moment, polarizability (α), the first hyperpolarizability (β) and the second hyperpolarizability (γ) values. The nonlinear optical response of TPB derivatives containing non-metal donor groups display linear relation with increased electron density. The calculated bond length alternation values decrease with increase in the electron density due to electron donating groups, indicating improvement in degree of conjugation. In case of TPB derivatives containing metal donor complexes the NLO properties increases with increase in dipole moment. We have observed that the tensor component along the bond X-axis of all the derivatives dominate the second order hyperpolarizabilities as compared to other components. The developed correlation shows clear dependence of hyperpolarizabilities on highest occupied molecular orbital and electrophilicity of the derivatives. Using time-dependent density functional theory, we investigated the excited-state properties of a series of TPB derivatives. On evaluating two-level model equation we have observed that hyperpolarizability of TPB have contribution both from change in dipole moment and transition dipole moment. Thus, these theoretical calculations predict the possible role of TPB derivatives as nonlinear material for optical devices.

A highly enantioselective Morita–Baylis–Hillman reaction of maleimides with isatin derived ketimines has been developed to obtain enantiomerically enriched 3-substituted-3-aminooxindoles using β-isocupreidine as an organocatalyst. Maleimide acting as a nucleophile provides products with up to 99% ee.

3-Substituted-3-aminooxindoles have attracted the attention of organic and medicinal chemists because these motifs constitute the core structure of a number of natural products and drug candidates. The catalytic potential of chiral organocatalysts and metal catalysts has been successfully exploited for the synthesis of enantioenriched 3-amino-2-oxindoles via the addition of various nucleophiles to isatin imines. This review focuses on the catalytic asymmetric synthesis of chiral 3-amino-3-substituted-2-oxindoles.

A highly enantioselective Friedel–Crafts reaction of activated phenols with isatin derivatives has been developed employing Cinchona-derived thiourea as an organocatalyst. A variety of biologically important 3-aryl-3-hydroxy-2-oxindoles have been synthesized using phenols in good to excellent yield with good enantioselectivity (up to 92% ee).

An organocatalytic asymmetric aza-Henry reaction of ketimines derived from isatins with nitroalkanes has been achieved using Cinchona alkaloid organocatalysts. This method works efficiently with several ketimines to produce a good (up to 82%) yield of the corresponding 3-substituted 3-amino-2-oxindoles with a good (up to 89%) enantiomeric excess.

An organocatalytic enantioselective Friedel–Crafts reaction of 1-naphthols with isatins has been developed employing bifunctional thiourea–tertiary amine organocatalysts. A variety of isatin derivatives react well with 1-naphthols in the presence of Cinchona derived thiourea 1a to provide biologically important chiral 3-aryl-3-hydroxy-2-oxindoles (3a–zg) in good yield (70–84%) and moderate to good enantioselectivity (37–83%).

3-Amino-2-oxindoles bearing tetra-substituted stereocenter are very important constituents of many bioactive and pharmaceutical agents. In the last few years, asymmetric organocatalysis emerged as an excellent approach for the synthesis of optically active 3-substituted-3-amino-2-oxindoles. This review describes the various organocatalytic enantioselective strategies for the synthesis of 3-substituted 3-amino-2-oxindole frameworks.Figure optionsDownload full-size imageDownload as PowerPoint slide

The recent emergence of biological activities of chiral 3-substituted-3-hydroxy-2-oxindoles has inspired synthetic chemists to develop new methodologies for their synthesis. Both chiral organocatalysts and organometallic catalysts have provided an important platform for their synthesis and in recent years, great achievements have been made in their catalytic asymmetric synthesis. This review summarizes the catalytic strategies for enantioselective synthesis of targeted frameworks.

The asymmetric organocatalytic conjugate addition reaction of various nucleophiles to the unsaturated acceptor provides an important route for the synthesis of valuable chiral entities. Recently, aromatic and hetero-aromatic compounds have been successfully used as nucleophiles in the enantioselective conjugate addition reaction. This review provides an overview on the recent developments made in organocatalytic enantioselective conjugate addition of arenes and hetero-arenes to unsaturated acceptors.

A new series of water compatible primary-tertiary diamine catalysts derived from natural primary amino acids bearing a hydrophobic side chain have been synthesized. These new primary-tertiary diamine-Brønsted acid conjugates bifunctional organocatalysts efficiently catalyzes the asymmetric direct syn selective cross-aldol reaction of different protected hydroxyacetone with various aldehydes in high yield (94%) and high enantioselectivity (up to 97% ee of syn) and dr of 91:9 (syn/anti) under mild reaction conditions.

The synthesis of enantiopure epoxides, as well as their corresponding vicinal diols is an actively pursued area of research. This is due to the fact that these compounds are essential chiral intermediates for the synthesis of bioactive products in the pharmaceutical and agrochemical industries. Therefore, the developments of efficient and cost effective processes for the preparation of these chiral molecules in enantiopure form are of importance. Epoxide hydrolase has emerged as an important enzyme for the asymmetric synthesis of enantiopure epoxides and diols via biocatalytic hydrolytic kinetic resolution (HKR) and enantioconvergent hydrolysis of racemic epoxides. The hydrolytic kinetic resolution of racemic epoxides provides a single enantiomer of the remaining epoxide and a single enantiomer of the formed diol whereas biocatalysts with complementary enantioselectivities and opposite regioselectivities provide the enantiopure diol as the only product, through enantioconvergent hydrolysis.Epoxide hydrolase has emerged as an important enzyme for the asymmetric synthesis of enantiopure epoxides and diols via biocatalytic hydrolytic kinetic resolution (HKR) and enantioconvergent hydrolysis of racemic epoxides. Hydrolytic kinetic resolution of racemic epoxides provides a single enantiomer of the remaining epoxide and a single enantiomer of the formed diol, whereas biocatalysts with complementary enantioselectivities and opposite regioselectivities provide enantiopure diols as the only product, through enantioconvergent hydrolysis.

The direct aldol reaction of 4-nitrobenzaldehyde and cyclohexanone, catalyzed by a protonated prolinamide catalyst in water, proceeds with the formation of aldol product that has high diastereoselectivity and enantioselectivity in an optimal pH range of 4–5.

α,α-Dicyanoolefins have emerged as versatile reactants, finding use as vinylogous nucleophiles, Michael acceptors and dienophiles in a variety of organic reactions. In the last few years, the reactivity of α,α-dicyanoolefins has been explored in various asymmetric transformations catalyzed by organocatalysts. In this review, we are presenting the recent advances in asymmetric organocatalytic transformations involving α,α-dicyanoolefins.

A new series of water compatible primary-tertiary diamine catalysts derived from natural primary amino acids bearing a hydrophobic side chain have been synthesized. These new primary-tertiary diamine-Brønsted acid conjugates bifunctional organocatalysts efficiently catalyzes the asymmetric direct syn selective cross-aldol reaction of different protected hydroxyacetone with various aldehydes in high yield (94%) and high enantioselectivity (up to 97% ee of syn) and dr of 91:9 (syn/anti) under mild reaction conditions.

A highly enantioselective Morita–Baylis–Hillman reaction of maleimides with isatin derived ketimines has been developed to obtain enantiomerically enriched 3-substituted-3-aminooxindoles using β-isocupreidine as an organocatalyst. Maleimide acting as a nucleophile provides products with up to 99% ee.