Abstract Treatment of 3-[(alkoxycarbonyl) alkyl]-substituted conjugated cycloalkenones with diisobutylaluminum hydride at-78 C followed by acid quenching furnishes spiro ethers, whereas the corresponding 3-(carboxyalkyl)-substituted cycloalkenones generate spiro lactones upon reaction with sodium borohydride at 30 C followed by acid quenching.
![1-oxaspiro[4.4]non-8-en-2-one Structure](https://image.chemsrc.com/caspic/316/86971-90-6.png)
![1-oxaspiro[4.5]dec-6-ene Structure](https://image.chemsrc.com/caspic/407/7129-25-1.png)