Henrik Sundén

One‐Pot Organocatalytic Domino Michael/α‐Alkylation Reactions: Direct Catalytic Enantioselective Cyclopropanation and Cyclopentanation Reactions

The development of one-pot organocatalytic domino Michael/alpha-alkylation reactions between bromomalonates or bromoacetoacetate esters and alpha,beta-unsaturated aldehydes is presented. The chiral-amine-catalyzed reactions with bromomalonates as substrates give access to the corresponding 2-formylcyclopropane derivatives in high yields with excellent diastereoselectivity and up to 99 % ee. The catalytic domino Michael/alpha-alkylation reactions between 4-bromo-acetoacetate and enals provide a route for the synthesis of functionalized cyclopentanones in good to high yields with 93-99 % ee. The products from the organocatalytic reactions were also reduced with high diastereoselectivity to the corresponding cyclopropanols and cyclopentanols, respectively. Moreover, one-pot combinations of amine and heterocyclic carbene catalysis (AHCC) enabled the highly enantioselective synthesis of beta-malonate esters (91-97 % ee) from the reaction between bromomalonates and enals. The tandem catalysis included the catalytic domino reaction followed by catalytic in situ chemoselective ring-opening of the 2-formylcyclopropane intermediates.

Small peptides as modular catalysts for the direct asymmetric aldol reaction: ancient peptides with aldolase enzyme activity

Simple peptides and their analogues having a primary amino group as the catalytic residue mediate the direct asymmetric intermolecular aldol reaction with high stereoselectivity and furnish the corresponding aldol products with up to 99% ee; this intrinsic ability of highly modular peptides may explain the initial molecular evolution of aldolase enzymes.

Nonlinear Effects in Asymmetric Amino Acid Catalysis by Multiple Interconnected Stereoselective Catalytic Networks

Nonlinear effects in asymmetric amino acid catalysis by multiple interconnected stereoselective catalytic networks