Yong Jian Zhang

Palladium-Catalyzed Asymmetric Decarboxylative Cycloaddition of Vinylethylene Carbonates with Michael Acceptors: Construction of Vicinal Quaternary Stereocenters†

An efficient method for the diastereo- and enantioselective construction of vicinal all-carbon quaternary stereocenters through palladium-catalyzed decarboxylative cycloaddition of vinylethylene carbonates with activated Michael acceptors was developed. By using a palladium complex generated in situ from [Pd2(dab)3]⋅CHCl3 and a phosphoramidite ligand as a catalyst under mild reaction conditions, the process provides multifunctionalized tetrahydrofurans bearing vicinal all-carbon quaternary stereocenters in high yields with a high level of absolute and relative stereocontrol.

Palladium‐Catalyzed Decarboxylative Cycloaddition of Vinylethylene Carbonates with Formaldehyde: Enantioselective Construction of Tertiary Vinylglycols

An efficient method for the enantioselective construction of tertiary vinylglycols through a palladium-catalyzed asymmetric decarboxylative cycloaddition of vinylethylene carbonates with formaldehyde was developed. By using a palladium complex generated in situ from [Pd2(dba)3]⋅CHCl3 and a phosphoramidite ligand as a catalyst under mild reaction conditions, the process allows conversion of racemic 4-substituted 4-vinyl-1,3-dioxolan-2-ones into the corresponding 1,3-dioxolanes, as methylene acetal protected tertiary vinylglycols, in high yields with good to excellent enantioselectivities.

Pd-Catalyzed Regioselective and Stereospecific Suzuki–Miyaura Coupling of Allylic Carbonates with Arylboronic Acids

The Pd-catalyzed Suzuki-Miyaura coupling reaction of unsymmetric 1,3-disubstituted secondary allylic carbonates with arylboronic acids has been developed in a wet solvent under a base-free system to afford allyl-aryl coupling products in a high level of isolated yields with complete regio- and E/Z-selectivities with good to excellent chemoselectivities. The coupling reaction of optically active allyl carbonates gave allyl-aryl coupling products with excellent enantioselectivities with inversion of the stereochemistry. This coupling method was successfully applied to the synthesis of (S)-naproxen.

Palladium-Catalyzed Enantioselective Decarboxylative Cycloaddition of Vinylethylene Carbonates with Isocyanates

An efficient method for the enantioselective construction of β-substituted β-vinylglycinol derivatives through palladium-catalyzed decarboxylative cycloaddition of vinylethylene carbonates with isocyanates was developed. By using a palladium complex generated in situ from [Pd2 (dba)3]⋅CHCl3 (dba=dibenzylideneacetone) and (S)-Segphos as a catalyst under mild reaction conditions, the process provided 4-substituted-4-vinyloxazolidin-2-ones in high yields with a high level of enantioselectivity. The stereochemical outcome of the reaction was explained by DFT calculations and the synthetic utility of the process was demonstrated by the gram-scale transformation and formal synthesis of MK-0731 as a kinesin spindle protein inhibitor.

Pd-Catalyzed Asymmetric Decarboxylative Cycloaddition of Vinylethylene Carbonates with Imines.

An efficient method for the enantioselective synthesis of β-tertiary β-amino alcohol derivatives through Pd-catalyzed decarboxylative cycloaddition of vinylethylene carbonates with imines was developed. By using a palladium complex generated in situ from [Pd2(dba)3]·CHCl3 and phosphoramidite L2 as a catalyst under mild reaction conditions, the process provided 4-substituted-4-vinyloxazolidines in good to high yields with high levels of enantio- and diastereoselectivities.

Highly efficient asymmetric organocatalytic Friedel–Crafts alkylation of indoles with α,β-unsaturated aldehydes

The development of an improved organocatalyst, N-isopropylated bipyrrolidine 2a, for the asymmetric Friedel-Crafts alkylation of indoles with alpha,beta-unsaturated aldehydes has been presented. The new organocatalyst readily facilitates the enantioselective alkylation reaction, providing 3-alkylated indoles in good to high yields (62-89%) with high levels of enantioselectivity (80-93% ee) using only 2 mol% of catalyst loading.

Enantioselective Construction of Tertiary C–O Bond via Allylic Substitution of Vinylethylene Carbonates with Water and Alcohols

An efficient method for the enantioselective construction of tertiary C-O bond via asymmetric allylic substitution of racemic vinylethylene carbonates with water and alcohols has been developed. Under the cooperative catalysis system of an in situ generated chiral palladium complex and boron reagent in mild conditions, the process allowed rapid access to valuable tertiary alcohols and ethers in high yields with complete regioselectivities and high enantioselectivities. This protocol represented the first example of direct enantioselective formation of a tertiary C-O bond with water as an oxygen donor. The synthetic utilities of the process have been demonstrated by the elaboration of the products into key intermediates of biologically relevant agents, and chiral tertiary cyclic ethers could also be provided through the sequential reactions of the allylic etherification and ring-closing metathesis.

Corrigendum: Palladium‐Catalyzed Asymmetric Decarboxylative Cycloaddition of Vinylethylene Carbonates with Michael Acceptors: Construction of Vicinal Quaternary Stereocenters

DOI: 10.1002/anie.201407013 In Table 1 of this Communication, the ligand L1–L7 was inadvertently displayed as S enantiomer whereas the R-configured ligand (shown below) was used throughout. Therefore, the proposed stereochemical outcome (Figure 2, and the second sentence in right column in the page 11259) is incorrect. The absolute configuration of C4 of the cyclized products 3 and 5 should be opposite to that of the cycloaddition products from vinylethylene carbonates with formaldehyde in previous work by the authors (cited as Ref. [7]).