An asymmetric organocatalytic domino oxa-Michael/1,6-addition reaction of ortho-hydroxyphenyl-substituted para-quinone methides and isatin-derived enoates has been developed. In the presence of 5 mol % of a bifunctional thiourea organocatalyst, this scalable domino reaction affords 4-phenyl-substituted chromans bearing spiro-connected oxindole scaffolds and three adjacent stereogenic centers in good to excellent yields (up to 98 %) and with very high stereoselectivities (up to >20:1 d.r., >99 % ee).
The first copper-catalyzed highly chemo-, regio-, diastereo-, and enantioselective Kinugasa/Michael domino reaction for the desymmetrization of prochiral cyclohexadienones is described. In the presence of a chiral copper catalyst, alkyne-tethered cyclohexadienones couple with nitrones to generate the chiral spirocyclic lactams with excellent stereoselectivity (up to 97 % ee, >20:1 dr). The new method provides direct access to versatile highly functionalized spirocyclic β-lactams possessing four contiguous stereocenters, including one quaternary and one tetra-substituted stereocenter.
A novel hollow-structured Mn/TS-1 catalyst has been reported as a non-nitric acid route for adipic acid production from oxidative cleavage of cyclohexanone. The method generates adipic acid in high yields with molecular oxygen under organic solvent-and promoter-free conditions. The hollow nature of the catalyst with large intra-particle voids facilitates the diffusion of bulky molecules to the internal catalytic site and increases the catalyst activity. The advantage of this catalyst is its reusability with almost consistent reactivity, thereby making it viable for industrial applications. † Electronic supplementary information (ESI) available. See
This review is covering the recent development of catalytic asymmetric domino reactions for the desymmetrization of alkene-, alkyne- and allene-tethered cyclohexadienones using transition metals and chiral ligands.
The efficient asymmetric synthesis of highly substituted succinimides from α,β-unsaturated aldehydes and α-ketoamides via NHC-catalyzed [3+2] cycloaddition has been developed. The new scalable protocol significantly expands the utility of NHC catalysis for the synthesis of heterocycles and provides easy access to assemble a wide range of succinimides from simple starting materials.
An NHC-catalyzed Michael/Michael/esterification domino reaction via homoenolate/enolate intermediates for the asymmetric synthesis of tetrasubstituted cyclopentanes is described.
An asymmetric organocatalytic domino oxa‐Michael/1,6‐addition reaction of ortho‐hydroxyphenyl‐substituted para‐quinone methides and isatin‐derived enoates has been developed. In the presence of 5 mol % of a bifunctional thiourea organocatalyst, this scalable domino reaction affords 4‐phenyl‐substituted chromans bearing spiro‐connected oxindole scaffolds and three adjacent stereogenic centers in good to excellent yields (up to 98 %) and with very high stereoselectivities (up to >20:1 d.r., >99 % ee).
The first example of an N-heterocyclic carbene-catalyzed asymmetric desymmetrization of enal-tethered cyclohexadienones via an intramolecular homoenolate Michael addition/esterification reaction is described. This new protocol offers a direct entry to various functionalized tetrahydrofluorenones with three contiguous stereocenters in high yields, good diastereoselectivities and excellent enantioselectivities.
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