Reactions of nucleophilic allymetal species generated in situ through 1,4-alkenyl-to-allyl metal migrations

• Main Author: Callingham, Michael
• Published: University of Nottingham 2018
• Subjects: QD241 Organic chemistry
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.757495

Herein is described the catalytic in situ generation of nucleophilic allylmetal species through the activation of allylic C-H bonds. Reactivity is achieved through initial carbometalation of an enyne, followed by the key 1,4-alkenyl-to-allyl metal migration which generates the allylmetal intermediate. This new mode of reactivity was firstly employed in the rhodium-catalysed diastereoselective reaction of arylboron reagents with enynones, to give products containing three contiguous stereocentres. Initial discovery and optimisation of this reaction was performed by Benjamin Partridge. Through use of a chiral sulfur olefin ligand, products could be obtained in high enantioselectivites. Secondly, a three-component coupling between 1,3-enynes, arylboronic acids and imines is described. The use of a chiral rhodium catalyst allowed the synthesis of a range of homoallylic amines with excellent control of stereoselectivity (>95:5 dr, up to 99% ee).