“Multicomponent Catalytic Synthesis of Organoboron Compounds
for Scalable Natural Product Synthesis”
Efficient catalytic reactions that generate C–C bonds enantioselectively and those that produce different types of alkenes diastereoselectively are central to research in modern chemistry. Transformations that accomplish these two tasks simultaneously in a single operation are highly prized, particularly if the catalysts, substrates and reagents are easily accessed at low cost and reaction conditions are mild. In this Lecture, we will discuss catalytic processes wherein organocopper intermediates generated in situ subsequently participate in chemo-, site- and enantioselective allylic substitution or 1,6-conjugate addition reactions. Products, which contain a stereogenic carbon center as well as a mono-substituted alkene or alkyne or an easily modifiable Z-trisubstituted alkenylboron group, are formed in up to 89% yield, with >98% branch- or 1,6:1,4 and stereoselectivity and >99:1 enantiomeric ratio. The copper-based catalysts are derived from a robust heterocyclic salt that can be prepared in multi-gram quantities from inexpensive starting materials and without costly purification procedures. Utility of the approach is showcased through enantioselective synthesis of gram quantities of several biologically active natural products.
Key References:
“Multifunctional Organoboron Compounds for Scalable Natural Product Synthesis,” F.Meng, K. P. McGrath, A. H. Hoveyda, Nature 2014, 513, 367.
“Catalytic Enantioselective 1,6-Conjugate Additions of Propargyl and Allyl Groups,” F.Meng, X. Li, S. Torker, Y. Shi, X. Shen, A. H. Hoveyda, Nature 2016, 537, 387.