γ-Acyl-and related δ-lactones having no 6 substituents were synthesized in a sequence of reactions, 1, 4-conjugate additions of sulfurstabilized acetate anions to α, β-unsaturated ketones, followed by trapping of the resultant ketone enolates with formaldehyde, mild lactonization, and desulfurization.
![7-acetyl-9-oxa-1,4-dithiaspiro[4.5]decan-10-one结构式](https://image.chemsrc.com/caspic/362/89665-11-2.png)
![7-propanoyl-9-oxa-1,4-dithiaspiro[4.5]decan-10-one结构式](https://image.chemsrc.com/caspic/324/89665-12-3.png)
![7-butanoyl-9-oxa-1,4-dithiaspiro[4.5]decan-10-one结构式](https://image.chemsrc.com/caspic/286/89665-13-4.png)
![7-acetyl-6-methoxy-9-oxa-1,4-dithiaspiro[4.5]decan-10-one结构式](https://image.chemsrc.com/caspic/248/89665-14-5.png)
