Bimetallic tandem catalysis-enabled enantioselective cycloisomerization/carbonyl-ene reaction for construction of 5-oxazoylmethyl α-silyl alcohol.

A bimetallic tandem catalysis-enabled enantioselective cycloisomerization/carbonyl-ene reaction was developed. The reaction proceeded well with a broad range of -propargylamides and acylsilanes, affording the target chiral 5-oxazoylmethyl α-silyl alcohols in up to 95% yield and 99% ee under mild conditions. Importantly, this facile protocol was available for the late-stage modification of several bioactive molecules.

Catalytic asymmetric addition of thiols to silyl glyoxylates for synthesis of multi-hetero-atom substituted carbon stereocenters.

A chiral Lewis acid-catalyzed enantioselective addition of thiols to silyl glyoxylates was developed. The reaction proceeds well with a broad range of thiols and acylsilanes, affording the target tertiary chiral α-silyl-α-sulfydryl alcohols with multi-hetero-atom carbon stereocenters in excellent yields (up to 99%) and enantioselectivities (up to 98% ee). A series of control experiments were conducted to elucidate the reaction mechanism.

Catalytic enantioselective ene-type reactions of vinylogous hydrazone: construction of α-methylene-γ-butyrolactone derivatives.

The catalytic asymmetric ene-type reactions of vinylogous hydrazone were accomplished by using chiral N,N'-dioxide-metal salt complexes as catalysts. A wide range of electrophiles, including isatins, α-ketoester, imines, and aldehydes reacted with (E)-2-methyl-N-(piperidin-1-yl)prop-2-en-1-imine efficiently, affording the corresponding homoallylic alcohols and amines in high yields (up to 99%) with excellent ee values (up to 99%). The methodology provided a convenient way to synthesize bioactive chiral α-methylene-γ-butyrolactone derivatives.

Dynamic kinetic asymmetric transformations of β-halo-α-keto esters by N,N'-dioxide/Ni(ii)-catalyzed carbonyl-ene reaction.

Dynamic kinetic asymmetric transformations of racemic β-halo-α-keto esters through carbonyl-ene reaction were realized using a chiral N,N'-dioxide-nickel(ii) complex, giving the corresponding β-halo-α-hydroxy esters containing two vicinal chiral tri- and tetrasubstituted carbon centers in good yields and dr with excellent ee values without the use of extra bases. Meanwhile, a proposed reaction mechanism was presented according to the configuration of the product.