ChemInform Abstract: Remarkable Product Selectivity During Photo-Fries and Photo-Claisen Rearrangements Within Zeolites.
✍ Scribed by K. PITCHUMANI; M. WARRIER; V. RAMAMURTHY
- Publisher
- John Wiley and Sons
- Year
- 2010
- Weight
- 34 KB
- Volume
- 28
- Category
- Article
- ISSN
- 0931-7597
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✦ Synopsis
Remarkable Product Selectivity During Photo-Fries and Photo-Claisen Rearrangements Within Zeolites.
-The influence of two types of zeolites (faujasites X and Y and pentasils ZSM-5 and ZSN-11) varying in size and shape on the product distribution in the photo-Fries rearrangement of phenyl acetate (I) and benzoate (V) and in the photo-Claisen rearrangement of allyl phenyl ether (VIII) is tested. While in solution (method A)) the ratio of ortho and para products is influenced by electronic factors, high selectivities in favor of the ortho isomers are observed in the presence of NaY and KY zeolites (methods B) and C)). In contrast, shape and size of pentasils are such that only the para products fit within the zeolites. However, no selectivity is observed in hexane ( method D)), since hexane displaces the reactants from the interior of the zeolite to the solvent. When photolysis is conducted in H2O ( method E)), high selectivities in favor of the para isomers are obtained, except for compound (V), which is to large to enter the pentasil zeolites. -(PITCHUMANI, K.;