ChemInform Abstract: Me₂AlCl‐Mediated Carboxylation, Ethoxycarbonylation, and Carbamoylation of Indoles.

Abstract

Me 2AlCl-Mediated Carboxylation, Ethoxycarbonylation, and Carbamoylation of Indoles. -(NEMOTO, K.; TANAKA, S.; KONNO, M.; ONOZAWA, S.; CHIBA, M.; TANAKA, Y.; SASAKI, Y.; OKUBO, R.; HATTORI*, T.; Tetrahedron 72 (2016) 5, 734-745, http://dx.doi.org/10.1016/j.tet.2015.12.028 ; Dep. Biomol. Eng., Grad. Sch. Eng., Tohoku Univ., Aoba, Sendai 980, Japan; Eng.) -M. Tismer 22-122

Synthesis of the Multidrug Reversal Agent Ko143 and Its Parent Natural Product Fumitremorgin C

“…While the persistence of the N(11)-benzyl group under mild hydrogenation conditions was not surprising, unfortunately, we were unable to achieve clean removal of the benzyl group from 18 under any other conditions investigated (see the Supporting Information), in spite of the fact that there is ample literature precedent for the N-debenzylation of indole derivatives. [27][28][29] In the absence of a plausible explanation for these observations, subsequent experimental work was focused on the exploration of other N(11)protecting groups on the indole nucleus. The corresponding variants of 17 bearing a PMB (19), a DMB (20), or an o-nitrobenzyl (ONB) group (21) on N(11) (Scheme 4) could be efficiently prepared through ZnCl 2mediated indole formation from the corresponding βamino ketone precursors (see the Supporting Information).…”