95936-18-8Relevant articles and documents
A unified synthesis of topologically diverse: Aspidosperma alkaloids through divergent iminium-trapping
Mijangos, Marco V.,Miranda, Luis D.
supporting information, p. 9409 - 9419 (2019/01/03)
Aspidospermidine, vincadifformine, 1,2-dehydroaspidospermidine, goniomitine, and quebrachamine, five Aspidosperma alkaloids distributed within three structurally diverse topologies, were synthesized from a single molecular scaffold, namely indole-valerolactam 6. This common intermediate can be divergently manipulated, through the incorporation of conformational and electronic constraints that influence the chemo-selectivity of the iminium ion derived therefrom, between three different reaction paths: N(1) vs. C(3) cyclization (indole numbering) vs. over-reduction. Moreover, a catalytic carbene insertion for direct C(3)-H indole functionalization is reported for the first time in an approach to goniomitine (4), and a following tandem ester reduction/iminium generation/cyclization secured its tetracyclic system. The development of a highly diastereoselective one-pot hemi-reduction/cyclization/deprotection process to obtain a cis-pyridocarbazole directly allowed the synthesis of pentacyclic Aspidosperma alkaloids 1, 2, and 3.
Palladium(II)-Catalyzed Allylic C H Oxidation of Hindered Substrates Featuring Tunable Selectivity Over Extent of Oxidation
Xing, Xiangyou,O'Connor, Nicholas R.,Stoltz, Brian M.
, p. 11186 - 11190 (2016/07/06)
The use of Oxone and a palladium(II) catalyst enables the efficient allylic C H oxidation of sterically hindered α-quaternary lactams which are unreactive under known conditions for similar transformations. This simple, safe, and effective system for C H activation allows for unusual tunable selectivity between a two-electron oxidation to the allylic acetates and a four-electron oxidation to the corresponding enals, with the dominant product depending on the presence or absence of water. The versatile synthetic utility of both the allylic acetate and enal products accessible through this methodology is also demonstrated.
Total synthesis of (±)-goniomitine via a formal nitrile/donor- acceptor cyclopropane [3 + 2] cyclization
Morales, Christian L.,Pagenkopf, Brian L.
, p. 157 - 159 (2008/09/18)
(Chemical Equation Presented) The total synthesis of (±)-goniomitine has been accomplished in 17 linear steps with 5.2% overall yield starting from commercially available δ-valerolactam. A synthetic highlight includes the first application of a formal [3 + 2] cycloaddition between a highly functionalized nitrile and a donor-acceptor cyclopropane to prepare an indole nucleus. The use of a microwave reactor is shown to greatly improve the reaction times for two steps.
