Construction of the ABC ring system of taxanes via stereoselective one-pot three-component coupling and intramolecular alkylation of a protected cyanohydrin ether

Construction of the ABC ring system of taxanes via one-pot three-component coupling and intramolecular alkylation is accomplished. The 1,4-addition of a protected cyanohydrin ether to 2-methyl-2-cyclohexenone and subsequent addition of the resulting enolate to formaldehyde proceeded stereoselectively to provide the AC ring in 90% yield. The stereoselective reduction of the 2-keto group was achieved by using hydroxy-directed hydride reduction with LiAlH₄. The intramolecular alkylation of the protected cyanohydrin ether furnished the ABC ring system of taxanes in 43% yield.