FRIEDEL-CRAFTS TYPE ALLYLATION OF ANISOLE WITH (SUBSTITUTED ALLYL) GERMANES

The Friedel-Crafts type reaction of (substituted allyl) triethylgerman es (1) with anisole was studied. When allylgermanes (1) were treated w ith two equimolar amounts of copper (II) chloride in anisole at room t emperature, the allylated products(2) were obtained in good yields. Th e regioselectivity of the reaction is largely affected by substituents on allylgermanes (1); a methoxyphenyl group is selectively introduced to the less substituted side of an allylic system. In the case of the reactions of regioisomeric (1,3-disubstituted allyl) germanes (1c and d), the allylated compounds(2) with almost the same product distribut ion were obtained regardless of the original location of triethylgermy l group. These results suggest that the present reaction proceeds via the allylic carbocation intermediate (4). It was found that the Friede l-Crafts type reaction of 1 was effected also with tin(IV) chloride, a nd the allylated products (2) were obtained with the similar regiosele ctivity observed in the copper(II) chloride-promoted reactions. On the basis of the fact that allyltriphenylstannane (6) was formed by the s uccessive treatments of allyltriethylgermane with tin(IV) chloride and phenylmagnesium bromide, it is assumed that the tin(IV) chloride prom oted reaction may proceed through the allyltrichlorostannane intermedi ate (5).