Rearranjo di-pi-metano de derivados de 3-Fenil-Propeno com retiradores de el?trons em C1

• Author(s): Silva, Francisco de Assis da
• Date: 2020
• Origin: Oasisbr
• Subject(s): Qu?mica; Qu?mica
• Document Type: Master thesis
• Language: Portuguese

Description

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Made available in DSpace on 2020-11-17T16:48:47Z (GMT). No. of bitstreams: 1 1990 - Francisco de Assis da Silva.pdf: 3729846 bytes, checksum: 6daf4b69868f1fbc84b7286942d5ce46 (MD5) Previous issue date: 1990-05-02

Coordena??o e Aperfei?oamento de Pessoal de N?vel Superior - CAPES

The photochemistry of derivatives of 1,1-dicyano-3-phenyl-propene was investigated. All compounds were dissubstituted at C1 by cyano or ester groups, or one of each; C3 had either one or two alkyl groups, besides the phenyl. The maln results were: (a) the quantum yields for di-pi-methane rearrangement depend on the nature the terminal electron-withdrawing substituents; (b) 1,1-dicyano-3-phenyl-butene shows the presence of two dlfferent mechanisms for cyclopropane formation, simultaneously; (c) compounds with at least. one terminal ester groups having a benzylic hydrogen, show photo-deconjugation as the preferred reaction pathway.

Investigou-se a fotoqu?mica de v?rios derivados de 3-fenll-propeno, todos dissubstitu?dos em C1, seja por grupos ciano. seja por carbometoxllas, Al?m disso, C3 portava uma, ou duas, alquilas. al?m da fenila. As observa??es principais foram: (a) varia??o no rendimento qu?ntico de rearranjo d1-pi-metano em fun??o da substitui??o em C1; (b) ocorr?ncia simult?nea de dois mecanismos para forma??o de c1clopropanos em 1,1-diciano-3-fenil-buteno; (c) predomin?ncia de desconjuga??o foto-induzida em compostos com carboalcoxila terminal e presen?a de hidrog?ni0 benz?lico.