Stereoselective Rh- and Cu-catalysed additions to imines and aldehydes

Chapter 1.Copper-Catalysed Borylative Coupling of Vinylazaarenes and N-Boc Imines. Methodology for the copper-catalysed three-component couplings of vinylazaarenes, bis(pinacolato)diboron, and N-Boc imines has been developed. Oxidation of the initially formed boron species gives azaarene-containing, Boc-protected amino alcohols with reasonable to good diastereoselectivities. Additionally the synthetic utility of the reaction products have been demonstrated. The crude boron species have been shown to undergo a Suzuki-Miyaura cross coupling to give further functionalised products. Finally, facile deprotection of the reaction products is possible. Chapter 2. Chain Walking of Allylrhodium Species in Rhodium-Catalysed Nucleophilic Allylations of Imines and Aldehydes. Allylrhodium species derived from δ-trifluoroboryl β,γ-unsaturated esters undergo chain walking towards the ester moiety. The resulting allylrhodium species react with imines to give products containing two new stereocenters and a Z-alkene. By using a chiral diene ligand, products can be obtained with high enantioselectivities. A pronounced matched/mismatched effect with the chirality of the allyltrifluoroborate is also observed. In an analogous reaction a rhodium-hydride species has been shown to catalyse the addition of diene esters and aldehydes via allylrhodium intermediates which also undergo chain walking towards the ester moiety. The methodology enables allylation of aromatic aldehydes with compounds containing both diene and ester functionalities linked by carbon chains of up to eight carbons in length