Cyclobutenedione-based method for the synthesis of substituted 2- pyridinones and dihydro-2-pyridinones

Article abstract of DOI:10.1021/jo990069t

1,2-Addition of N-Boc-protected α-amino carbanions to cyclobutenediones followed by methylation of the resulting alkoxides generated 4-(1-N-Boc- aminoalkyl)-4-methoxy-3-cyclobutenones. Removal of the Boc protecting group and thermal ring expansion gave dihydro-2-pyridinones in good yields. Treatment of the dihydro-2-pyridinones with NBS/pyridine led to the formation of the corresponding 2-pyridinones. This methodology proved general with regard to both the cyclobutenediones and α-amino carbanions.