A adição de aliltrimetilsilano, promovida por TiCl 4 , 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.The TiCl 4 -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.
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Ao prof.Dr. Hans Viertler pela orientação e exemplo de dedicação à Química tanto no aspecto da pesquisa quanto no de seu ensino.À prof.a Dra. Vera Lúcia Pardini pela colaboração e apoio constante. À prof.a Dra. Liliana Marzorati por seu otimismo, incentivo e grande amizade.À minha avó Olga por tudo o que fez por mim e a minha tia Catharina pelo interesse e incentivo, apesar da distância ...
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