Construction of a key intermediate in the asymmetric synthesis of chiral taxanes
Abstract
The radical bromination of acetal 5 followed by zinc-promoted fragmentation gives the highly functionalised, homochiral cyclohexane 7, which possesses the carbon skeleton of the C-ring of taxol; nucleophilic addition of dimethyllithium cuprate to 8, followed by ozonolysis gives aldehyde 10, ozonolysis of 8 gives aldehyde 9.