摘要 |
A compound of formula (Ia) or (Ib), wherein A and B each independently represents hydrogen or one, two or three naphthylidene substituents, which substituents are selected from C1-6 alkyl, C1-6 alkoxy, aryl, aryloxy, silyl and silyloxy; R<1> represents phenyl, C1-6 alkyl, phenyl C1-6 alkyl or a moiety of formula (a): wherein R2 represents C1-6 alkyl, phenyl or benzyl, R<3> represents H or OR<4> wherein R<4> is C1-6 alkyl or C1-6 alkylsilyl and n is zero or an integer 1 or 2; and X is a counter ion; a process for the preparation of such compounds and the use of such compounds for enantioselectively epoxidising a prochiral olefin.
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