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1,5-Asymmetric induction in boron-mediated aldol reactions of beta-alkoxy methylketones
Luiz C Dias1, Anderson A de Marchi, Marco A B Ferreira
1Instituto de Química, Universidade Estadual de Campinas, UNICAMP, C.P. 6154, 13084-971 Campinas, SP, Brazil. ldias@iqm.unicamp.br
Abstract:
Good levels of substrate-controlled, 1,5- syn-stereoinduction are obtained in boron-mediated aldol reactions of beta-trichloromethyl-beta-alkoxy and beta-trifluoromethyl-beta-alkoxy methylketones with achiral aldehydes, independent of the nature of the beta-alkoxy protecting group (TBS or PMB). In the case of boron aldol reactions of beta-aryl-beta-alkoxy methylketones, the 1,5- anti-adducts were obtained with high levels of diastereoselectivity only with a beta-OPMB group.
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