ABOUT THE REACTION OF 2,3-DIBROMO-2-METHYL-N-(1-ADAMANTYL)-PROPANAMIDE WITH SODIUM TERT-BUTOXIDE. A COMPETITION EXPERIMENT

2,3-Dibromo-2-methyl-N-(1-adamantyl)propanamide (4), a precursor equally suited for the preparation of an α-lactam and a β-lactam, upon treatment with sodium tert-butoxide ether gives no α-lactam (5), but an excellent yield of the isomeric β-lactam, 1-(1-adamantyl)-3-bromo-3-methylazetidinone (6) as the only product. Repeating the experiment using a large excess of sodium tert-butoxide still leads to β-lactam 6 in 76.1% yield, but now accompanied by its dehydrobrominated derivative, β-lactam 7, in 17.4% yield, and no trace of α-lactam 5