The exploration and expansion of the scope of the isothiourea-mediated synthesis of dihydropyridinones is presented. The use of ketimines derived from α,β-unsaturated γ-ketoesters as the Michael acceptor in a Michael addition/lactamisation cascade gives access to a range of dihydropyridinones with high enantioselectivity. The nature of the N-sulfonyl group present on the ketimine is extensively investigated, with further studies into derivatisation of the dihydropyridinone core also reported.