Synthesis of sulfinylated methylbenzoquinones and study of their facial diastereoselectivity in Diels-Alder reactions aiming the obtention of terpenic natural products precursors. / Síntese e estudo de diastereosseletividade facial, em reações de Diels-Alder, de metilbenzoquinonas sulfiniladas visando a obtenção de precursores de produtos naturais terpênicos

AUTOR(ES)

José Eduardo Pandini Cardoso Filho

DATA DE PUBLICAÇÃO

2003

RESUMO

Our main objective is to take advantage of the well known π-facial diastereoselectivity of (SS)-2-tolylsulfinyl-1,4-benzoquinones, in the Diels-Alder reactions, to obtain, via photo-thermal olefin metathesis, enantiopure precursors of capnellene and ikarugamycin. The formation of an inseparable mixture of products in the reaction of commercially available methylcyclopentadiene and (SS)-2-tolylsulfinyl-1,4-benzoquinone made this route unsuitable for obtaining capnellene. For the synthesis of ikarugamycin, the 5 and 6-methyl-2-(SS)-tolylsulfinyl-1,4-benzoquinones were prepared but, in spite of the good π-diastereoselectivity they exhibited, in the reaction with 1,3-cyclohexadiene, spontaneous elimination of sulfenic acid from the formed adducts precluded their use. In an attempt to overcome this very easy elimination, a chlorinated quinone was synthesized but it showed oxidizing properties in the presence of 1,3-cyclohexadiene.

ASSUNTO(S)

síntese orgânica diels-alder diels-alder diastereosseletividade facial sulfinil metilbenzoquinona organic syntheses produtos naturais compostos de enxofre sulfinyl methylbenzoquinone facial diastereoselectivity

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