Asymmetric enamine catalysis.

After an initial period of validating asymmetric organocatalysis by using a wide range of important model reactions that constitute the essential tools of organic synthesis, the time has now been reached when organocatalysis can be used to address specific issues and solve pending problems of stereochemical relevance. This Review deals with selected studies reported in 2006 and the first half of 2007, and is intended to highlight four main aspects that may be taken as testimony of the present status and prospective of organocatalysis: a) chemical efficiency; b) discovery of new substrate combinations to give new asymmetric syntheses; c) development of new catalysts for specific purposes by using mechanistic findings; and d) applications of organocatalytic reactions in the asymmetric total synthesis of target natural products and known compounds of biological and pharmaceutical relevance.

Asymmetric Organocatalysis: From Infancy to Adolescence

Alan Ford,† Hugues Miel, Aoife Ring,† Catherine N. Slattery,† Anita R. Maguire,*,†,‡ and M. Anthony McKervey* †Department of Chemistry and ‡School of Pharmacy, Analytical and Biological Chemistry Research Facility, Synthesis and Solid State Pharmaceutical Centre, University College Cork, Cork, Ireland Almac Discovery Ltd., David Keir Building, Stranmillis Road, Belfast BT9 5AG, United Kingdom Almac Sciences Ltd., Almac House, 20 Seagoe Industrial Estate, Craigavon BT63 5QD, United Kingdom

Modern Organic Synthesis with α-Diazocarbonyl Compounds

Recent Advances in Asymmetric Organocatalytic 1,4-Conjugate Additions

Catalytic C-C bond-forming multi-component cascade or domino reactions: pushing the boundaries of complexity in asymmetric organocatalysis.

Pyrrolidine-thiourea as a bifunctional organocatalyst: highly enantioselective Michael addition of cyclohexanone to nitroolefins.

Enantioselective formal [3+3] annulation for the direct construction of bicyclic skeletons with four stereogenic centers.

Cyclic ketones react with (E)-2-nitroallylic acetates in the presence of catalytic pyrrolidine-thiourea, which affords bicyclic skeletons with four or five stereocenters in one single reaction with up to 98 % ee in moderate to high yields. The cooperative effects of both enamine and the Bronsted acid are found to be crucial for the high reactivity and enantioselectivity of this cascade reaction, which is demonstrated by both theoretical calculation and experimental data.

An Organocatalytic Asymmetric Tandem Reaction for the Construction of Bicyclic Skeletons

An organocatalytic asymmetric Michael addition of ketones to alkylidene malonates has been developed In the presence of 20 mol % of urea 1a or N-(pyrrolidin-2-ylmethyl)trifluoromethanesulfonamide 1j, the reactions of ketones with alkylidene malonates afford the desired Michael adducts in moderate to good yields with good to high enantioselectivities under mild conditions

Enantioselectively Organocatalytic Michael Addition of Ketones to Alkylidene Malonates

The first example of catalytic asymmetric [1,2]-Stevens rearrangement reaction of 1,3-oxathio-lanes with diazomalonates has been developed and up to 90% ee is achieved by the bisoxazoline 4e/ copper(II) triflate [Cu(OTf) 2 ] complex.

Ligand-Accelerated Asymmetric [1,2]-Stevens Rearrangment of Sulfur Ylides via Decomposition of Diazomalonates Catalyzed by Chiral Bisoxazoline/Copper Complex

Chun-Li Cao

Papers

Pyrrolidine-thiourea as a bifunctional organocatalyst: highly enantioselective Michael addition of cyclohexanone to nitroolefins.

Enantioselective formal [3+3] annulation for the direct construction of bicyclic skeletons with four stereogenic centers.

An Organocatalytic Asymmetric Tandem Reaction for the Construction of Bicyclic Skeletons

Enantioselectively Organocatalytic Michael Addition of Ketones to Alkylidene Malonates

Ligand-Accelerated Asymmetric [1,2]-Stevens Rearrangment of Sulfur Ylides via Decomposition of Diazomalonates Catalyzed by Chiral Bisoxazoline/Copper Complex