Asymmetric organocatalytic conjugate addition of malonates to enones using a proline tetrazole catalyst.

5-Pyrrolidin-2-yltetrazole performs as a useful organocatalyst for the asymmetric addition of malonates to a range of enones, with good to excellent enantioselectivities.

A versatile organocatalyst for the asymmetric conjugate addition of nitroalkanes to enones.

5-Pyrrolidin-2-yltetrazole performs as an improved catalyst for the asymmetric addition of a range of nitroalkanes to cyclic and acyclic enones, with good to excellent enantioselectivity.

A general organocatalytic enantioselective malonate addition to alpha,beta-unsaturated enones.

A general enantioselective organocatalytic conjugate addition procedure of a variety of malonates to alpha,beta-unsaturated enone systems is presented. The reaction is efficiently catalysed by the pyrrolidinyl tetrazole catalyst 1. Cyclic, acyclic and aromatic enones can be used and the reaction with ethyl malonates 3 b provides the Michael addition products in high yields with good to excellent enantioselectivities. Since only 1.5 equivalents of malonate are used as a reagent, the reaction is readily scaled and practical to operate. Furthermore, the malonate addition products can be easily mono decarboxylated without loss in enantiomeric excess by enzymatic or sodium hydroxide mediated methods.

An efficient, asymmetric organocatalyst-mediated conjugate addition of nitroalkanes to unsaturated cyclic and acyclic ketones.

5-Pyrrolidin-2-yltetrazole is a versatile organocatalyst for the asymmetric conjugate addition of nitroalkanes to enones. Using this catalyst, this transformation requires short reaction times, tolerates a broad substrate scope, and possibly proceeds via generation of an iminium species.