Zhan-Ming Zhang

A New Type of Chiral Sulfinamide Monophosphine Ligands: Stereodivergent Synthesis and Application in Enantioselective Gold(I)‐Catalyzed Cycloaddition Reactions

A simple, new type of chiral sulfinamide monophosphines, the so-called Ming-Phos ligands, is reported; these ligands could be easily prepared from inexpensive and commercially available starting materials. The Ming-Phos ligands performed well in the enantioselective gold-catalyzed cycloaddition reaction of 2-(1-alkynyl)-alk-2-en-1-ones with nitrones. Both enantiomers of the products could be obtained in good yields and with excellent diastereo- and enantioselectivity through transformations that were catalyzed by gold complexes derived from two diastereomers of Ming-Phos ligand M5 (Ar=1-naphthyl).

Diastereo- and Enantioselective Copper(I)-Catalyzed Intermolecular [3+2] Cycloaddition of Azomethine Ylides with β-Trifluoromethyl β,β-Disubstituted Enones

Reported herein is an asymmetric [3+2] cycloaddition reaction of azomethine ylides with β-trifluoromethyl β,β-disubstituted enones, a reaction which is enabled by a Ming-Phos-derived copper(I) catalyst (Ming-Phos=chiral sulfinamide monophosphines, Figure ). This method provides scalable and efficient access to the highly substituted pyrrolidines with a trifluoromethylated, all-carbon quaternary stereocenter in good yields with up to greater than 20:1 d.r. and 98 % ee. The reaction has a broad substrate scope and tolerates a wide range of functional groups.

Enantioselective gold-catalyzed intermolecular [2 + 2]-cycloadditions of 3-styrylindoles with N-allenyl oxazolidinone

The enantioselective intermolecular [2 + 2] cycloaddition of 3-styrylindoles with N-allenyl oxazolidinone has been achieved for the first time by the employment of a Xiang-Phos derived chiral gold-catalyst. The corresponding cycloadducts could be obtained in good yields (up to 95%) with up to 95% ee.

Enantioselective Regiodivergent Synthesis of Chiral Pyrrolidines with Two Quaternary Stereocenters via Ligand-Controlled Copper(I)-Catalyzed Asymmetric 1,3-Dipolar Cycloadditions

An unprecedented ligand-controlled regiodivergent Cu(I)-catalyzed asymmetric intermolecular (3 + 2) cycloaddition reaction of α-substituted iminoesters with β-fluoromethyl β,β-disubstituted enones was developed. This novel strategy provides an efficient method for the enantioselective regiodivergent synthesis of pyrrolidines bearing two adjacent quaternary stereocenters or two discrete quaternary stereocenters, opening up a new era for medicinal chemistry and diversity-oriented synthesis. DFT calculations showed that the P,N-ligand L2 acts as a pseudobidentate ligand. The formation of a O-Cu bond with the carbonyl oxygen atom of the enone and dissociation of the amine nitrogen of L2 from the Cu(I) center occurs during the catalytic cycle; this is the main reason for the tuning the regioselectivity of the cycloaddition reaction caused by switching of the ligand. The salient features of this work include high yields (up to >99%), a general substrate scope, the use of commercially available ligands, and high regio-(up to >20:1 rr), diastereo- (up to >20:1 dr), and enantioselectivity (up to >99% ee).

Cu(I)-catalyzed Michael addition of ketiminoesters to β-trifluoromethyl β,β-disubstituted enones: rapid access to 1-pyrrolines bearing a quaternary all-carbon stereocenter

A highly chemo-, diastereo-, and enantioselective Cu(I)/(S,S)-iPr-FOXAP-catalyzed Michael addition of ketiminoester to β-trifluoromethyl β,β-disubstituted enones was developed. This method provides facile access to highly functionalized 1-pyrrolines bearing two contiguous stereocenters, including a trifluoromethylated all-carbon quaternary stereocenter, via one-pot hydrolytic cyclization (up to >20 : 1 cr, > 20 : 1 dr, and 98% ee). The addition of trace amounts of water to the direct 1,3-dipolar cycloaddition is crucial for obtaining 1-pyrrolines with high chemoselectivities rather than pyrrolidines.

Direct Asymmetric Formal [3 + 2] Cycloaddition Reaction of Isocyanoesters with β-Trifluoromethyl β,β-Disubstituted Enones Leading to Optically Active Dihydropyrroles

A highly enantioselective copper-catalyzed [3 + 2] cycloaddition reaction of α-isocyanoesters with β,β-disubstituted enones has been developed. Dihydropyrroles were obtained in excellent yields and enantioselectivity by employing an inexpensive copper catalyst. This process provides a scalable and efficient route for the synthesis of highly enantioselective 2,3-dihydropyrroles bearing a trifluoromethylated all-carbon quaternary stereocenter. The salient feautures of this reaction include high efficiency, operational simplicity, high diastereoselectivity and enantioselectivity, a broad substrate scope, outstanding functional group tolerance, and products exhibiting high utility for further transformations.

Palladium‐Catalyzed Enantioselective Reductive Heck Reactions: Convenient Access to 3,3‐Disubstituted 2,3‐Dihydrobenzofuran

The first example of highly enantioselective intramolecular hydroarylation of allyl aryl ethers was realized by palladium-catalyzed reductive heck reactions utilizing a new chiral sulfinamide phosphine ligand (N-Me-XuPhos). N-Me-XuPhos can be easily prepared on gram scale from readily available starting materials in a one-pot synthesis approach. A series of optically active 2,3-dihydrobenzofurans bearing a quaternary stereocenter were obtained in good yields and with excellent enantioselectivities. The practicality of this reaction was validated in the straightforward synthesis of CB2 receptor agonists. Moreover, deuterium was efficiently incorporated into the products.

Ming-Phos/Gold(I)-Catalyzed Diastereo- and Enantioselective Synthesis of Indolyl-Substituted Cyclopenta[c]furans

A highly enantioselective gold(I)-catalyzed intermolecular tandem cyclization/[3 + 2] cycloaddition of 2-(1-alkynyl)-2-alken-1-ones with 3-stylindoles was achieved by using Ming-Phos as a chiral ligand. A variety of chiral highly substituted cyclopenta[ c]furans were obtained in good yields (up to 99%) with excellent diastereoselectivities (>20:1) and enantioselectivities (up to 97% ee). The salient features of the present protocol include mild conditions, excellent yields, and high diastereo- and enantioselectivities, using readily available starting materials and a chiral ligand.