The invention relates to a process for the manufacture of vinylchromanes. This process is concerned with the manufacture of the compounds having the formula ##STR1## wherein R.sup.o is hydrogen or a cleavable protecting group, and comprises cyclizing a compound having the formula ##STR2## wherein R.sup.o is defined above and R.sup.1 is --CH.sub.2 --CH.sub.2 --C(W)(CH.sub.3)--CH.dbd.CH.sub.2 or --CH.sub.2 --CH.sub.2 C(CH.sub.3).dbd.CH--CH.sub.2 --W where W is a leaving group, by means of a chiral transition metal-diphosphine complex. The compounds of formula I are useful intermediates, e.g. in the manufacture of (R,R,R)-.alpha.-tocopherol.
本发明涉及一种制备
乙烯基环己烷的方法。该方法涉及制备具有公式##STR1##其中R.sup.o是氢或可裂解保护基的化合物,并通过手性过渡
金属
二膦配合物环化具有公式##STR2##其中R.sup.o如上所述,R.sup.1是--CH.sub.2 --CH.sub.2 --C(W)(CH.sub.3)--CH.dbd.CH.sub.2或--CH.sub.2 --CH.sub.2 C(CH.sub.3).dbd.CH--CH.sub.2 --W,其中W是离去基团。公式I的化合物是有用的中间体,例如在(R,R,R)-.alpha.-
生育酚的制造中。