Direct Catalytic Enantioselective Vinylogous Aldol Reaction of α-Branched Enals with Isatins

A catalytic asymmetric hetero-Diels-Alder reaction of olefinic azlactones and isatins: facile access to chiral spirooxindole dihydropyranones

A catalytic asymmetric hetero-Diels-Alder (HDA) reaction has been achieved through hydrogen-bond directed γ-addition of olefinic azlactones to isatins. This methodology provides an efficient access to spirooxindole dihydropyranones in moderate to good yields and with excellent enantioselectivities.

Trienamine catalysis for asymmetric Diels–Alder reactions of 2,4-dienones: a theoretical investigation

In the Diels–Alder reactions of 2,4-dienones with two dienophiles, cinchona alkaloid acts as an efficient bifunctional catalyst by generating an extended trienamine π-conjugated system and by orienting the dienophile at an appropriate position for a cycloaddition reaction.

Asymmetric synthesis of 3,3'-spirooxindoles fused with cyclobutanes through organocatalytic formal [2 + 2] cycloadditions under H-bond-directing dienamine activation

The first organocatalytic asymmetric synthesis of a spirooxindole skeleton incorporated with a cyclobutane moiety has been successfully developed on the basis of H-bond-directing dienamine activation. Structurally complex spirocyclobutyl oxindoles, which possess four contiguous stereocenters, including one spiro quaternary center, were obtained in good yields (up to 83%) with excellent β,γ-regioselectivity (>19:1) and stereocontrol (up to >19:1 dr and 97% ee).

Asymmetric synthesis of tetrahydroquinolines through a [3+2] cycloaddition controlled by dienamine catalysis

A dienamine-mediated enantioselective 1,3-dipolar cycloaddition catalyzed by a chiral prolinol silyl ether catalyst has been developed. Removal of the benzamide group of the intermediates could furnish chiral C-1 substituted tetrahydroisoquinolines (see scheme) in high yields and excellent stereoselectivities.

Chiral metal phosphate catalysis: highly asymmetric hetero-Diels–Alder reactions

A highly enantioselective hetero-Diels–Alder reaction of α-keto esters and isatins catalyzed by chiral calcium BINOL-derived phosphates (X-ray) is reported.

Aqueous Morita-Baylis-Hillman reaction of unprotected isatins with cyclic enones

The readily available bicyclic imidazolyl alcohol 1 is a unique catalyst for the aqueous Morita-Baylis-Hillman (MBH) reaction between unprotected isatins and cyclic enones that gives access to a variety of potentially very useful 3-substituted 3-hydroxy-2-oxindoles in an operationally simple, efficient, and environmentally friendly way. The hydroxyl group of the catalyst is believed to stabilize the betaine intermediate formed in the first step of the MBH reaction.

Organocatalyzed asymmetric synthesis of dihydrodibenzofurans based on a dienamine process

The first organocatalyzed asymmetric method for the synthesis of dihydrodibenzofurans based on a dienamine process has been developed. This two-step protocol works with a broad range of substrates and delivers only the cis-diastereomer in good yield with up to 91% ee. The enantioenriched products have been transformed to highly functionalized and partially hydrogenated dibenzofurans in excellent diastereoselectivities.