Nickel-catalyzed cross-couplings of unactivated secondary and tertiary alkyl halides and photoinduced copper-mediated asymmetric C-N cross-couplings

摘要

Chapter 1 describes the development of two nickel-catalyzed Suzuki cross-coupling methodologies that employ alkyl halides as electrophiles. In Section 1.1, asymmetric [gamma]-alkylation relative to a carbonyl group is achieved via the stereoconvergent cross-coupling of racemic secondary [gamma]-chloroamides with primary alkylboranes. Section 1.2 describes the first Suzuki carbon-carbon bond-forming reaction using tertiary alkyl halides as electrophiles; specifically, unactivated tertiary alkyl bromides are cross-coupled with arylboranes. Chapter 2 describes the establishment of photoinduced asymmetric copper-mediated C-N Ullmann-type coupling processes between racemic secondary alkyl halides and N-heterocycles. Preliminary yields and enantioselectivities for a reaction between secondary benzylic halides and carbazoles, with the use of a monodentate chiral phosphine ligand, are presented. The methodology is then extended to secondary [alpha]-haloamides, including [alpha]-halolactams, which are found to afford very promising yields and enantioselectivities.