Pivalaldehyde → HCID 86614127, compound

A solution of N-allyl-N-t-butylcarbamate-(4′S)-6′-(bromo)-3′,4′-dihydrospiro[cyclobutane-1,2′-pyrano[2,3-b]pyridin]-4′-amine (4.12 g, 10.1 mmol) in ether (80 mL) was cooled to −78° C. and then t-butyllithium (12.5 ml, 21.3 mmol) was added and stirred for 15 minutes before the pivalaldehyde (3.80 ml, 35.0 mmol) (Note: freshly distilled) was added. After 5 minutes, LC-MS shows the starting material has been consumed. The reaction was quenched with sat'd NH4Cl and the organic layer separated. The organic layer was combined with previous trial reactions and adsorbed onto a plug of silica gel and chromatographed through a Redi-Sep® pre-packed silica gel column (120 g), eluting with 0% to 30% EtOAc in hexane, to provide N-allyl-N-t-butylcarbamate-(4′S)-6′-(1-hydroxy-2,2-dimethylpropyl)-3′,4′-dihydrospiro[cyclobutane-1,2′-pyrano[2,3-b]pyridin]-4′-amine as a yellow oil. MS m/z: 417 (M+1).