Researchers in Japan have developed a process for asymmetric synthesis of optically active alcohol derivatives. Yutaka Ukaji and his colleagues at the Division of Material Sciences, Kanazawa University, Kanazawa, Japan, converted a divinyl carbinol —1,4-pentadien-3-ol — to optically active trans-pyrazolidines at enantioselectivities as high as 99%. The researchers term their development an attractive and unique reaction scheme that could be useful for preparation of optically active nitrogen- and oxygen-containing chemicals.
The route involves the desymmetrization of the divinyl carbinol by the asymmetric 1,3-dipolar cycloaddition of azomethine imines using diisopropyl (R,R)-tartrate as the chiral auxiliary. The resultant trans-pyrazolidines contain a double bond and a hydroxyl group on the size chain. More details appear in a recent article in Chemistry, A European Journal.
The researchers now are using the method to synthesize optically active and biologically active compounds.
The approach suits not only divinyl carbinols but also other allylic and homoallylic alcohols, notes Ukaji.
Key challenges are reducing the level of the chiral auxiliary to the catalytic amount, replacing the solvent with a more environmentally benign one, and successfully scaling up the process, he says.