Site selectivity phenyl substituted alkenes

Phenyl hydroperoxide, C-O distance, 103 (y-Phenylhydroperoxides, nucleophiUc substitution cyclization, 234-5 1 -Phenyl-3-methyl-3-butene, intrazeohte photooxygenation, 874-5 Phenyl substituted alkenes, photooxidation site selectivity, 839-42... 

Use of Aluminate Reagents Derived from 1-Alkenes. The nucleophilic substitution was achieved using lithium tetraalkylaluminates produced by the Ti-catalyzed hydroalumination reaction of 1-alkenes with UAIH4 (5). The whole transformation is illustrated in Scheme 7, and the results are summarized in Table 6. Because the hydroalumination is site-selective, optically active phenyl-substituted or olefinic trifluoro alcohols are now readily available. 

M425>. Here the selectivity was only low with respect to the site of addition, which could be either the benzoyl or 4-substituted benzoyl group. Phenyl glyoxylates can also be successfully utilized as reactive carbonyls in the Paterno-Btichi reaction as demonstrated by Hu and Neckers <1997JOC564>. Oxetanes were formed in very high yields with electron-rich (e.g., polyalkylated) alkenes, but with monosubstituted alkenes there was no oxetane formation due to the prevalence of Norrish II type hydrogen abstraction (Scheme 22). 

Selective oxidation of styrene to acetophenone by a Pd(II) catalyst in the presence of ionic liquids has been achieved (equation 27). Electronic effects on the site ofPd(II) oxidation of substituted styrenes are indicated in equation (28). Strong pi-donation from the phenyl substituent favors oxidation at the alkene carbon alpha to the aromatic ring. 

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