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A Lewis-acid catalyzed intermolecular Diels–Alder reaction between multisubstituted acyclic dienes and the E and Z isomers of α,β-enals was studied. It was found that the diene reacted selectively with the Z-isomer of the α,β-enal.

A novel, four-component synthetic strategy to synthesize a series of β-difluoroalkyl unsaturated esters/amides with high regioslectivity is described. This Pd-catalyzed difluoroalkylation and carbonylation reaction can be carried out with simple starting materials. Through this protocol, two new C–C bonds (including one C–CF2 bond) and one C–O(N) bond are constructed simultaneously in a single step. The synthetic utility of this reaction system has been certified by the applicability to a wide scope of alkynes and nucleophiles. Preliminary mechanistic studies suggest that the difluoroalkyl radical pathway is involved in this reaction.

A method for the synthesis of trifluoromethyl CF3-substituted spirocyclic compounds containing with a unique quaternary carbon center from readily available starting materials has been developed. The reaction provides a facile access to 2H-azirines via cascade cyclization. These compounds constitute a new class of functionalized synthetic intermediates, which can be used for the synthesis of various nitrogen-containing heterocycles and biologically active CF3-containing compounds.

The remarkable exo-selectivities of most of the products may be due to steric interaction between the bulky Lewis acid and the substrates.

The direct assembly of acrylonitriles and valuable 2H-azirines from readily available starting materials is described. This novel alkyne difunctionalization reaction proceeded under mild reaction conditions. Considering the versatile roles of 2H-azirines, this work paves the way for further modification into various heterocycles.

Copper-catalyzed enantioselective 1,4-conjugate addition of methyl 4,4,4-trifluorocrotonate with aliphatic Grignard reagents to access an asymmetric tertiary carbon center attached with a trifluoromethyl group was achieved under mild reaction conditions. The desired products could be obtained in reasonable yields and good enantioselectivities.

A practical and efficient strategy has been described for the preparation of 4-quinolone derivatives. Using commercially available diethyl acetylenedicarboxylate and aromatic amines as starting materials, the synthetic protocol has been achieved and afforded the product via hydroamination at room temperature followed by PPA-catalyzed intramolecular ring closure. The products can be easily obtained in high yields. Conditions and mechanism of the reaction have also been investigated. This protocol is environmentally friendly and transition-metal-free, with advantages including short reaction time, convenient operation, and mild reaction conditions.

This work describes an efficient α-alkylation reaction of α-amino aldehydes with 3-indolylmethanols. In the promotion of catalyst 3f, the target products were obtained in high yields (up to 99%), good diastereoselectivities (up to 88:12), and excellent enantioselectivities (up to 96% ee). The direct alkylation products can be readily converted into other tryptophan derivatives without the loss of stereoselectivities.

Primary and secondary aliphatic amines react at room temperature with oxanorbornene (I) to yield bicyclic adducts (III) whereas anilines produce significant amounts of (Z)-β-enamine esters (VI) as side products.

The 1,1′-bi-2-naphthol–ZnEt2–Ti(OiPr)4–Cy2NH system is found to catalyze the 1,3-enyne addition to aliphatic aldehydes as well as other aldehydes at room temperature with 75–96% yield and 82–97% ee. This system is also broadly applicable for the highly enantioselective reaction of other alkyl-, aryl-, and silylalkynes with structurally diverse aldehydes. The propargylic alcohols prepared from the catalytic asymmetric enyne addition to aliphatic aldehydes are used to prepare a series of optically active trienynes. In the presence of a catalytic amount of [RhCl(CO)2]2 and 1 atm of CO, the optically active trienynes undergo highly stereoselective domino Pauson–Khand/[4 + 2] cycloaddition to generate optically active multicyclic products. The Rh(I) catalyst is also found to catalyze the coupling of a diyne with CO followed by [4 + 2] cycloaddition to generate an optically active multicyclic product. These transformations are potentially useful for the asymmetric synthesis of polyquinanes containing a quaterna...

Highly chemoselective and stereoselective tandem Pauson–Khand/[4+2] cycloaddition leads to efficient construction of the spirotricyclic core analogue of mangicol A.

The reaction allows a convenient access to highly functionalized cyclopentenones as versatile building blocks.

In DMSO cleavage of triethylsilyl (TES) ethers by o-iodoxybenzoic acid (IBX) was significantly faster than cleavage of tert-butyldimethylsilyl (TBS) ethers or further oxidation into carbonyl compounds. In most cases, TES protecting groups could be removed in good to excellent yields within 1 h, whereas similar TBS protecting groups remained intact under the same conditions. The procedure also could be adapted for direct one-pot conversion of TES ethers into carbonyl compounds.

Dithianes and dithiolanes at benzylic or allylic carbons can easily be hydrolyzed by IBX in DMSO, whereas non-activated dithianes/dithiolanes are much more stable under these conditions.