The addition of allyltrimethylsilane to cyclic N-acyliminium ions derived from(S)-(+)-mandelic acid and cyclohexyl-based chiral auxiliaries
Título del documento: The addition of allyltrimethylsilane to cyclic N-acyliminium ions derived from(S)-(+)-mandelic acid and cyclohexyl-based chiral auxiliaries
Revista: Journal of the Brazilian Chemical Society
Base de datos: PERIÓDICA
Número de sistema: 000310986
ISSN: 0103-5053
Autores: 1

2
Instituciones: 1Universidade Estadual de Campinas, Instituto de Quimica, Campinas, Sao Paulo. Brasil
2Universidade de Sao Paulo, Instituto de Quimica, Sao Paulo. Brasil
Año:
Periodo: Ago
Volumen: 12
Número: 4
Paginación: 507-513
País: Brasil
Idioma: Inglés
Tipo de documento: Artículo
Enfoque: Experimental, aplicado
Resumen en inglés The TiCl4- promoted addition of allyltrimethylsilane to chiral 5- and 6-membered N-acyliminium ions employing (S)-(+)-mandelic acid, (1R,2S)-trans-2-phenyl-1-cyclohexanol and (1R,2S,5R)-8-phenylmenthol derivatives as chiral auxiliaries occurred with low to moderate diastereoisomeric ratios (1:1-6:1) to afford 2-substituted amides and carbamates in good yields. The best diastereoselection was observed with (1R,2S,5R)-8-phenylmenthol as the chiral auxiliary. The 2-substituted amides and carbamates were converted to the corresponding alkaloids (S)- and (R)-propyl pyrrolidine and coniine with efficient recovery of the chiral auxiliaries
Resumen en portugués A adição de aliltrimetilsilano, promovida por TiCl4, a íons N-aciliminios cíclicos de 5- e 6-membros derivados do ácido (S)-(+)-mandélico, (1R,2S)-trans-2-fenil-1-cicloexanol e (1R,2S,5R)-8-fenilmentol ocorreu com baixas a moderadas razões diastereoisoméricas (1:1-6:1) e forneceu as respectivas amidas e carbamatos em bons rendimentos. A melhor diastereosseleção facial foi observada com o uso de (1R,2S,5R)-8-fenilmentol como auxiliar quiral. As amidas e carbamatos 2-substituídos foram convertidos nos alcalóides (S)- e (R)-propil pirrolidina e coniina com eficiente recuperação dos auxiliares quirais
Disciplinas: Química
Palabras clave: Química orgánica,
Acido mandélico,
Auxiliares quirales,
Ciclohexil,
Iones N-aciliminio,
Derivados de pirrolidina,
Derivados de piperidina
Keyword: Chemistry,
Organic chemistry,
Mandelic acid,
Chiral auxiliaries,
Cyclohexyl,
N-acyliminium ions,
Pyrrolidine derivatives,
Piperidine derivatives
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