Cobalt-Catalyzed MCRs Containing Organoboron Compounds

1 Cobalt-Catalyzed MCRs Containing Organoboron Compounds 

In this first example, a cobalt(I)-catalyzed Diels-Alder reaction employing alkynyl boron derivatives 2 and 1,3-diene 1 for preparation of dihydroaromatic building blocks 4 is disclosed. Ensuing, dihydroaromatic boronic ester intermediates 3 were used as useful synthetic scaffolds in an unusual thermal Diels-Alder reaction with different dienophiles, generating highly substituted and functionalized products in acceptable to very good yields by recrystallization after four synthetic steps. Five new C—C bonds from four simple components were formed in this process. 

Multicomponent Reactions Concepts and Applications for Design and Synthesis, First Edition. Edited by Raquel R Herrera and Eugenia Marquds-L6pez. 2015 John Wiley Sons, Inc. Published 2015 by John Wiley Sons, Inc. 

SCHEME 4.1 Cobalt(I)-catalyzed Diels-Alder reaction for the synthesis of polycyclic multifunctionalized products. 

SCHEME 4.2 Multicomponent cobalt-catalyzed l,4-hydrovinylation/aUylboration. dppe, l,2-bis(diphenylphosphino)ethane. 

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