SEQUENTIAL [2,3]WITTIG AND CLAISEN REARRANGEMENT: A FACILE SYNTHETIC METHOD FOR (E,E)-4,7-ALKADIENALS AND -ALKADIENOIC ACIDS. A NEW FORMAL SYNTHESIS OF (±)-CERULENIN
SEQUENTIAL [2,3]WITTIG AND CLAISEN REARRANGEMENT: A FACILE SYNTHETIC METHOD FOR (E,E)-4,7-ALKADIENALS AND -ALKADIENOIC ACIDS. A NEW FORMAL SYNTHESIS OF (±)-CERULENIN
Four newsigmatropicsequences triggered by the regiocontrolled [2,3]-Wittig rearrangement of unsymmetrical bis-allylic ethers (1) to the l,5-dien-3-ols (2) arc described, which provide unique, regiocontrolled methods for the synthesis of a wide variety of unsaturatedcarbonylcompounds possessing interesting molecular frameworks. The newly developed sequences include the [2,3]-Wittig-Claisen, the