Abstract Treatment of carbonyl compounds with SmI 2 and methyl chloroformate in the presence of molecular sieves provides the cyclic carbonates or biscarbonates of pinacols. This one-pot reaction proceeds rapidly even with aliphatic ketones. The stereochemistry obtained by this procedure is different from that of conventional pinacolic couplings.
![11,13-dioxadispiro[4.0.46.35]tridecan-12-one Structure](https://image.chemsrc.com/caspic/475/91328-29-9.png)