Graft of chiral amino alcohol onto poly(menthyl vinyl ketone) and the grafted polymer’s inducement to the asymmetric addition of phenylacetylene to aromatic ketone

Abstract

A new kind of optically active polymer bearing chiral amino alcohol was prepared by means of graft. The resulting grafted polymer was obtained as follows. First, the carbonyl of optically active helical poly(menthyl vinyl ketone)(poly-MVK) was reduced to hydroxyl group with lithium aluminum hydride as a reductant to yield poly(1-menthyl-2-propen-1-ol)(poly-MPO). Second, the hydroxyl group of poly-MPO reacted with epichlorohydrin to yield methyloxirane-loading poly-MPO[(poly-MPO)-MO]. Third, the(poly-MPO)-MO reacted with amine to produce optically active polymer bearing chiral amino alcohol[(poly-MPO)-APO]. The (poly-MPO)-APO was applied to the asymmetric addition of phenylacetylene to aromatic ketone. Good enantioselectivities were achieved and the catalyst could be recovered and reused 5 times with unchanged enantioselectivity and slightly decreased activity.