Journal article

A regio- and stereocontrolled access to 2,4-dienols by amide/alcoholate-promoted ring-opening of dihydropyrans

Dihydropyrans I (R = R1 = H, R2 = H, Me, CH2CH2CH:CMe2; R = Me, CH2CHMe2, R1 = H, R2 = Me; R = R2 = H, R1 = CH:CMe2), when treated with LiN(CHMe2)2-KOCMe3, underwent smooth ring cleavage through b-elimination to give dienols (Z)-HOCHRCR1:CR2CH:CH2. Methylenetetrahydropyrans II (R3 = Me, CH2CHMe2) gave HOCHR3CH2C(CH:CH2):CH2, while II (R3 = H) gave (E)-HOCH2CH:CMeCH:CH2. Other cyclic or acyclic homoallylic ethers reacted similarly. [on SciFinder (R)]


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