Reorganization Reactions of Olefins

Many transition metal complexes catalyze the isomerization of olefins (Manuel, 1962 Cramer and Lindsey, 1966 Davies, 1967 Hubert and Reim-linger, 1970 Maitlis, 1971 Bingham er a/., 1974). 

These reactions are only of synthetic importance when there is some other functionality in the molecule that either stabilizes a particular olefin isomer or irreversibly blocks the isomerization process. For example, 1-octene is iso-merized into a mixture of 2,3- and 4-octenes in the presence of PdCl2/HOAc (Davies, 1964) while this same catalyst converts allylbenzene mainly into rra/M-) -methylstyrene. [Eq. (136) (Cruickshank and Davies, 1966)]. 

One of the most useful olefin isomerizations is the conversion of allyl alcohols into aldehydes and ketones [Eqs. (137) (Sasson and Rempel, 1974) and (138) (Strohmeier and Weigelt, 1975)]. 

This isomerization is a basis of using allyl ethers as protecting groups for alcohols [Eq. (139) (Corey and Suggs, 1973)]. 

Unconjugated dienes are readily brought into conjugation in the presence of iron carbonyl compounds. Usually, the less sterically crowded of the pos- 

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