Manganese(III)-mediated radical cyclisations for the (Z)-selective synthesis of exo-alkylidene pyrrolidinones and pyrrolidines.

The cyclisation of alkynyl amido- and amino-malonates in the presence of manganese(III) acetate gives exo-alkylidene pyrrolidinones and pyrrolidines with a preference for the (Z)-alkene product isomer.

Asymmetric cobalt-catalyzed Diels-Alder reactions of a boron-functionalized 1,3-diene with alkynes and allylboration with aldehydes.

[Structure: see text] A cobalt(I)-catalyzed Diels-Alder reaction of a 1-boron-functionalized 1,3-diene is the key step in a one-pot reaction interconnecting three simple starting materials to obtain a multifunctionalized product. This product incorporates a stereogenic quaternary center next to a stereogenic secondary alcohol functionality generated with a very high degree of regio- and diastereoselectivity and good enantioselectivity in the presence of a chiral ligand such as (S,S)-Norphos.

A simple cobalt catalyst system for the efficient and regioselective cyclotrimerisation of alkynes.

The intermolecular cyclotrimerisation of terminal and internal alkynes can be catalysed by simple cobalt complexes such as a CoBr2(diimine) under mild reaction conditions when treated with zinc and zinc iodide with high regioselectivity in excellent yields.