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The difluoromethylation of N-arylsulfonyl hydrazones with difluorocarbene generated from difluoromethylene phosphobetaine (Ph3P+CF2CO2−) to give various difluoromethyl aryl sulfones is described.

Asymmetric tandem Michael–Michael reactions between 2-substituted malonates and low reactive enones have been achieved by using novel dipeptides-derived phosphonium salts, affording the synthetically useful and highly functionalized chiral cyclopentanes with good yields, diastereoselectivities and high enantioselectivities.

The hydroperfluoroalkylation of electron-deficient olefins with perfluoroalkyl iodides promoted by a zinc/viologen system is described. Interestingly, no iodoperfluoroalkylation product was observed without the presence of radical H-donor.

A new trifluoromethylating reagent Cu(O2CCF2SO2F)2, which easily decomposes to generate active CuCF3 species in DMF at room temperature, has been conveniently prepared from inexpensive starting materials on a large scale. This new reagent can be applied to efficiently trifluoromethylate a variety of haloarenes under mild conditions, providing good-to-excellent yields of the desired products.

A novel and efficient route for the generation of pyrazolo[5,1-a]isoquinolines via 1,3-dipolar cycloaddition reaction of 1,3-dipolar and ethyl acetoacetate is described. Meanwhile, the selective synthesis of either pyrazolo[5,1-a]isoquinoline-1-carboxylate or 2-(pyrazolo[5,1-a]isoquinolin-2-yl)acetate derivatives from the same reactants has been achieved by simply varying base and reaction conditions.

The O-difluoromethylation of 1,3-diones with S-difluoromethyl sulfonium salt is described. The sulfonium salt was previously believed to be a direct difluoromethylation reagent, but our mechanistic investigation reveals that the O-difluoromethylation reaction proceeds not only via the direct transfer of the CF2H group, but also via a difluorocarbene process. This work represents the first protocol for mild O-difluoromethylation of acyclic 1,3-diones.

A new approach to functionalized γ-butenolides based on reagent-controlled tandem reaction sequences of Morita–Baylis–Hillman-type vinyl epoxides is described. The nucleophilic addition of a tertiary phosphine to the electron-deficient alkene led to ring-opening of the epoxide followed by lactonization to produce phosphonium ylides, which could undergo Wittig olefination with aryl trifluoromethyl ketones and aryl aldehydes to give 3-alkenyl γ-butenolides in moderate to good yields and high E/Z selectivity. Tertiary amine promoted the Michael-type addition of carbon- and nitrogen-based nucleophiles to the vinyl epoxides followed by lactonization to provide diverse 3-substituted γ-butenolides.

A small library of benzoxazine-fused isoquinolines has been synthesized under microwave irradiation (MW) via CuI-catalyzed domino reactions of o-alkynyl aldehydes and amines having embedded nucleophiles. This strategy offers a operationally simple, environmentally acceptable route to synthesize benzoxazine-fused isoquinolines in moderate to good yields. All new compounds were characterized by 1H NMR, 13C NMR, infrared, and high-resolution mass spectrometry techniques.

A highly enantioselective α-amination of 3-substituted oxindoles with azodicarboxylates catalyzed by amino acids-derived chiral phosphine catalysts is reported. The corresponding products containing a tetrasubstituted carbon center attached to a nitrogen atom at the C-3 position of the oxindole were obtained in high yields and with up to 98% ee.

This simple method is extended to the reaction of alkynes with aldehydes and electron-deficient ketone (VII).

A Pd-catalyzed enantiospecific formal [3 + 2] cycloaddition between chiral aziridines and indoles has been developed. With this method, chiral pyrroloindolines in enantiomerically pure forms were constructed in high yields and diastereoselectivities under mild conditions.

A novel family of chiral phase-transfer catalysts is developed and shown to demonstrate high efficiency in the reaction between 6- or 7-substituted conjugate enones and malonates.

A phosphine-promoted [3 + 2] cycloaddition from readily accessible MBH (Morita–Baylis–Hillman) carbonate and aryl trifluoromethyl ketone is described. The use of methyl vinyl ketone-derived allylic carbonate rather than common acrylate-derived counterpart renders the reaction pathway exclusive for 5-endo process, which enables the expeditious preparation of a range of trifluoromethylated 2,3-dihydrofuran in a chemospecific manner.

The title asymmetric Michael addition of α-fluoro-β-ketoesters to nitroolefins affords the adducts in good yields with high diastereoselectivities and enantioselectivities.

Enantioselective Robinson-type annulation reaction between β-ketoamide and α,β-unsaturated ketone is developed by utilizing the amino acid derived diamine catalysts.

Desymmetrization of meso-aziridines with aromatic thiols was realized by using α-amino acids-derived chiral quaternary phosphonium salts catalysts to provide chiral β-amino sulfides with high yields (up to 99%) and in moderate enantioselectivities (up to 70%).

This method uses new bifunctional phosphines and methyl acrylate which in situ generate zwitterions serving as catalysts for asymmetric Mannich-type and aza-Henry reactions through a homogeneous ion-pairing mode.

The combination of the chiral phosphine (PTU) and methyl acrylate efficiently catalyzes the Mannich reaction of cyclic β-ketoesters and N-Boc aldimines.

In addition to the propargylation of benzofuranones, this scalable method is also applicable to the corresponding transformation of indanone [cf.

Tandem vinylogous addition/lactonization/Wittig reaction of trifluoromethyl ketones with allylic carbonates provides γ-butenolides.

A series of 4-fluoro-pyrazole derivatives were synthesized in moderate to good yields via a one-pot tandem procedure involving an Rh-2(OAc)(4)-catalyzed C-H insertion and an electrophilic fluorination with N-fluorobenzenesulfonimide (NFSI). (C) 2014 Elsevier Ltd. All rights reserved.

Tandem nucleophilic/intramolecular cyclization of 2-(arylalkynyl)benzaldehydes and TmsCF3 offers an efficient one-pot synthesis of phthalans.

An efficient method for the construction of chiral spirooxindole-chroman and spirooxindole-tetrahydrothiophene scaffolds with three consecutive chiral centers including an all-carbon quaternary spirocenter has been developed. This method features an asymmetric thia/oxa-Michael-Michael cascade sequence in a single operation in the presence of chiral tertiary amine-thioureas as the catalysts, providing the desired products in good chemical yields and optical purities.

DABCO catalyzed the cross-Rauhut-Currier/transesterification reaction of alpha-cyano-alpha,beta-unsaturated ketones and aryl acrylates was discovered. The reaction rate law was determined by an integral method under pseudo-first-order reaction conditions, which assisted in proposing the mechanism of cross-Rauhut-Currier reaction promoted by Bronsted acid and establishing the rate-determining step.

Novel enantiopure phosphonium phase transfer catalysts derived from amino acids are developed.

Depending on the used phosphine organocatalyst, the reaction of activated ketones (I) and allenoates (II) yields either tertiary dienols or furan derivatives with quaternary stereocenters.

A novel type of bifunctional thiourea-ammonium salt is developed and their use as chiral phase-transfer catalyst in aza-Henry reactions between amidosulfones and nitroalkanes is demonstrated.

The advanced intermediate (XIII) can be transformed to 9-deoxygelsemide (XV) as described elsewhere.

New chiral bifunctional thiourea-phosphonium salts have been developed based on natural amino acids as highly efficient phase-transfer catalysts in the enantioselective aza-Henry reaction.

Lithium bis(perfluorooctylsulfonyl) imide efficiently catalyzes the acetylation of alcohols and phenols.

Both aromatic and aliphatic α,β—unsaturated aldehydes can be utilized in this operationally simple protocol for preparation of spiroindoles.

The title synthesis is successfully achieved by using the readily available and air-stable catalyst.

Enantiomerically enriched fluorine-containing multifunctional molecules containing adjoining chiral fluorine-substituted quaternary and tertiary centers are obtained in good yields and high dia- and enantioselectivities.

The asymmetric epoxidation of alpha,beta-unsaturated ketones has been achieved by using functional and readily accessible primary-secondary diamines as the catalysts, giving the useful alkyl epoxy products with good yields and high enantioselectivities (up to 99% ee).

A novel and facile preparation of 1,1-difluoroallyl substituted five-membered lactones or pyrrolidines in moderate yields through direct double electrophilic fluorination of 4,5-allenoic acids or tosylamides with SelectfluorTM F-TEAD-BF4 is described.

Organocatalyzed cascade reactions between cyclic β-enamino esters and α,β-unsaturated aldehydes have been developed. They provide highly substituted indolo[2,3-a]quinolizidines and benzo[a]quinolizidines in moderate to good yields and with good to excellent enantioselectivities. Both aromatic and aliphatic α,β-unsaturated aldehydes react readily with enamino esters to furnish the desired products.

An enantioselective Michael addition of ethyl 4,4,4-trifluoro-3-oxobutanoate to α,β-unsaturated ketone esters using a chiral alkyl-substituted thiourea catalyst is reported. Excellent levels of stereo-induction (up to 98% ee) under mild reaction conditions were obtained to afford the corresponding α-trifluoromethyldihydropyrans.

Chiral amino acids have played a key role in the development of organocatalysis from a biomimetic concept to an independent methodology, together with metal catalysis and enzyme catalysis, comprising the three major catalytic methodologies in modern organic synthesis. As an excellent pool for the design of organocatalysts, chiral amino acids have two obvious advantages: ready availability with usually affordable costs and modular structures allowing facile tuning of the catalytic efficiency. Recently, bifunctional/multifunctional primary–secondary amines, tertiary amine–thioureas, aminophosphines easily prepared from simple acyclic amino acids have been developed as efficient organocatalysts for various asymmetric reactions leading to a variety of useful chiral compounds. In this perspective, we present a personal overview of some of these recent advances in this field based on our own research experience.

A cascade sequence between cyclic hemiacetals and tryptamines was developed, which provided efficient access to highly substituted diazaindeno[2,1-α]phenanthrenes in moderate to good yields with high diastereoselectivities and good to excellent enantioselectivities. Hemiacetals were prepared by asymmetric organocatalyzed conjugate addition of cyclic 1,3-diketones to α,β-unsaturated aldehydes. Hemiacetals with various R1, both aromatic and aliphatic, were examined for the cascade sequence.

Bifunctional cinchona alkaloids were used to catalyze a tandem intramolecular oxa-Michael addition/decarboxylation reaction of alkylidene β-ketoesters 1, providing a series of flavanone derivatives with up to 97% yield and 93% ee.

Asymmetric [4 + 2] cycloaddition of β,γ-unsaturated α-keto esters (I) and (IV) with oxazolones (II) proceeds with excellent diastereoselectivity and high enantioselectivity (up to 97% e.e.) in the presence of a quinidine-derived bifunctional organocatalyst (NQD).

A prolinol-derived silyl ether efficiently catalyzes the one-pot Michael addition/Pictet—Spengler reaction of β-ketoamides with α,β-unsaturated aldehydes.