Directive effect of β-functionalization on the regiochemistry of the base induced homoketonization of bridgehead substituted 1,3-bishomocubane acetates

Base induced homoketonization of bridgehead acetate $\text{6}$ leads to the thermodynamically favored half cage skeleton $\text{7}$, whereas cage opening of $\text{5}$ is directed by the β-ketofunction to give cleavage of the central C₅–C₆ bond producing half cage diketone $\text{10}$.