Remote transmission of reactivity in rhodium-catalysed reactions

Herein is described the remote transition of reactivity in two different rhodium-catalysed transformations. The first example utilises the rare migration of an allylrhodium species generated in situ from conjugated dienes along a carbon chain towards tethered functional groups in a process known as allylrhodium chain walking. A remote nucleophilic allylation with an electrophile (aldehydes or imines) gives homoallylic alcohol or amine products in high diastereoselectivities. The second transformation sees reactivity transmitted through an initial carbometalation of an alkyne followed by the key 1,4˗alkenyl˗to˗aryl migration in the desymmetrisation of tethered cyclic and acyclic alkynones to give cyclisation products with an (E)-1-arylidene-1,2,3,4-tetrahydronaphthalene core. Using a chiral (S)˗DTBM-Segphos® ligand gave the products in high enantioselectivities.