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.