The radical cyclization approach to the morphine alkaloids has been applied in an asymmetric synthesis of (-)-dihydrocodeinone. A chiral cyclohexenol (R-32), from the CBS reduction of the enone, is the source of chirality. The first key step, tandem closure in which stereochemistry is controlled by geometric constraints,(-)-15b→(+)-16, was followed by an unprecedented reductive hydroamination, completing the synthesis of (-)- ...
![4-methyl-N-[2-(3-oxocyclohexen-1-yl)ethyl]benzenesulfonamide Structure](https://image.chemsrc.com/caspic/038/144318-24-1.png)
