Double Conjugate Addition of a Nitropropionate Ester to a Quinone Monoketal: Synthesis of an Advanced Intermediate to (±)-Gelsemine

A double conjugate addition between the lithium dianion of ethyl 3-nitropropionate and p-benzoquinone dimethyl ketal afforded a mixture of diastereomeric [3.2.1]bicylooctanones. These products were converted into an advanced intermediate previously carried forward to (±)-gelsemine by Fukuyama and Liu.