Michael addition of N- and O-centred nucleophiles to tethered acrylates. The role of double bond geometry in controlling the diastereoselectivity of cyclisations leading to 2,6-disubstituted tetrahydropyrans and piperidines

Cyclisation of substrates 1–4 occurs readily to give the corresponding 2,6-disubstituted tetrahydropyran or piperidine. The geometry about the carbon–carbon double bond of the Michael acceptor within the substrate is shown to have a significant impact on the diastereoselectivity of the cyclisation process.