Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/25122
Type: Artigo de periódico
Title: The addition of allyltrimethylsilane to cyclic N-acyliminium ions derived from(S)-(+)-mandelic acid and cyclohexyl-based chiral auxiliaries
Author: D'Oca, Marcelo G. M.
Pilli, Ronaldo A.
Pardini, Vera L.
Curi, Denise
Comninos, Francisco C. M.
Abstract: 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.
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.
Subject: (S)-(+)-Mandelic acid
cyclohexyl-based chiral auxiliaries
N-acyliminium ions
pyrrolidine and piperidine derivatives
Editor: Sociedade Brasileira de Química
Rights: aberto
Identifier DOI: 10.1590/S0103-50532001000400011
Address: http://dx.doi.org/10.1590/S0103-50532001000400011
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532001000400011
Date Issue: 1-Aug-2001
Appears in Collections:Unicamp - Artigos e Outros Documentos

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