Catalytic Diastereoselective Pauson−Khand Reaction: an Efficient Route to Enantiopure Cyclopenta[<i>c</i>]proline Derivatives

Cyclopenta[c]proline derivatives were synthesized in a stereocontrolled manner and in good yields via catalytic Pauson−Khand reactions. The starting materials, optically pure enyne amino acid derivatives, can be easily prepared by an alkenylboronic acid-mediated Mannich-type reaction

Zn(II)-Mediated Alkynylation−Cyclization of <i>o</i>-Trifluoroacetyl Anilines: One-Pot Synthesis of 4-Trifluoromethyl-Substituted Quinoline Derivatives

A novel efficient route to 4-trifluoromethyl-substituted quinoline derivatives through the Zn(II)-mediated alkynylation−cyclization of o-trifluoroacetyl anilines is described

High Diastereoselectivity in Intermolecular Carbonyl Ylide Cycloaddition with Aryl Aldehyde Using Methyl Diazo(trifluoromethyl)acetate

Methyl diazo(trifluoromethyl)acetate undergoes Rh2(OAc)4 catalyzed reaction with aryl aldehyde to form 1,3-dioxolanes bearing a C-4 trifluoromethyl group diastereoselectively in excellent yield

Studies toward the Total Synthesis of Nagelamide K

A stereocontrolled strategy toward the synthesis of nagelamide K has been developed. The dimeric imidazole acrylate, diimidazolidenesuccinate, was constructed as a synthetic precursor by a Ni-catalyzed coupling reaction; the microwave-promoted intramolecular aza-Michael addition afforded the imidazo[1,5-a]pyridine core structure of nagelamide K in high stereoselectivity. A detaurine–dediamino analogue of nagelamide K has been prepared

Highly Enantioselective Alkynylation of <i>α</i>-Keto Ester: An Efficient Method for Constructing a Chiral Tertiary Carbon Center

The asymmetric addition of terminal alkynes to α-keto ester was carried out using a catalytic amount of (1S,2S)-3-(tert-butyldimethylsilyloxyl)-2-N,N-(dimethylamino)-1-(p-nitrophenyl)-propane-1-ol in the presence of Zn(OTf)2 to give the corresponding tertiary propargylic alcohols in high yields with up to 94% ee. N-Methylephedrine and Zn(OSO2CHF2)2 were also examined in this reaction

Enantioselective Synthesis for the (−)-Antipode of the Pyrazinone Marine Alkaloid, Hamacanthin A

A short enantioselective total synthesis for the (−)-antipode of the antifungal marine alkaloid, hamacanthin A, (6R)-3,6-bis(6-bromoindol-3-yl)-5,6-dihydro-2(1H)-pyrazinone, is described. This synthesis proceeds through the coupling of 3-indolyl-α-oxoacetyl chloride and 3-indolyl azidoethylamine, followed by intramolecular aza-Wittig type cyclization. A concise and useful approach for the synthesis of (1R)-1-(indol-3-yl)-2-azidoethylamine using the Sharpless asymmetric dihydroxylation reaction followed by stereospecific azidation is also presented

Selective Aerobic Oxidation of Alcohols to Aldehydes, Carboxylic Acids, and Imines Catalyzed by a Ag-NHC Complex

Silver NHC catalysts have been developed for the selective oxidation of alcohols to aldehydes or carboxylic acids in the presence of BnMe₃NOH or KOH under dry air. The aerobic oxidation conditions are mild, and the yield is excellent. Further tandem catalysis enables the one-pot synthesis of imines in excellent yield. Only 0.1 mol % of the catalyst is required

Stereocontrolled Synthesis of the 22<i>E</i>,24β(<i>S</i>)-Trifluoromethyl Steroidal Side Chain and Its Application to the Synthesis of Fluorinated Analogues of Naturally Occurring Sterols

Stereocontrolled Synthesis of the 22E,24β(S)-Trifluoromethyl Steroidal Side Chain and Its Application to the Synthesis of Fluorinated Analogues of Naturally Occurring Sterol

Preparing Functional Bis(indole) Pyrazine by Stepwise Cross-coupling Reactions: An Efficient Method to Construct the Skeleton of Dragmacidin D

A direct approach for selective construction of properly substituted bis(indole) pyrazine, the skeleton of a marine alkaloid dragmacidin D, has been developed. The key steps involved the regioselective introduction of two indole units, using the palladium(0)-catalyzed Suzuki and the Stille cross-coupling reactions sequentially

[2.2]Paracyclophane-Derived Chiral P,N-Ligands: Design, Synthesis, and Application in Palladium-Catalyzed Asymmetric Allylic Alkylation

With the idea of tuning structural flexibility and rigidity, several [2.2]paracyclophane-derived P,N-ligands were designed and synthesized. A full investigation of the relationship between the ligands’ structures and their abilities to induce asymmetry in palladium-catalyzed asymmetric allylic alkylations of malonates with 1,3-diphenyl 2-propenyl acetate was carried out, and high yields and enantioselectivities (i.e., 99% yield, 97% ee) were observed while using ligands bearing matched planar and central chirality