2122-68-1Relevant academic research and scientific papers
Studies on difficult intramolecular hydroaminations in the context of four syntheses of alkaloid natural products
Dion, Isabelle,Vincent-Rocan, Jean-Francois,Zhang, Lei,Cebrowski, Pamela H.,Lebrun, Marie-Eve,Pfeiffer, Jennifer Y.,Bedard, Anne-Catherine,Beauchemin, Andre M.
, p. 12735 - 12749 (2014/01/17)
Examples of intramolecular alkene hydroaminations forming six-membered ring systems are rare, especially for systems in which the double bond is disubstituted. Such cyclizations have important synthetic relevance. Herein we report a systematic study of these cyclizations using recently developed Cope-type hydroamination methodologies. Difficult intramolecular alkene hydroaminations were used as key steps in syntheses of 2-epi-pumiliotoxin C, coniine, N-norreticuline and desbromoarborescidine A. This effort required the development of optimized hydroamination conditions to improve the efficiency of the cyclizations. Collectively, our results show that Cope-type cyclizations can be achieved on a variety of challenging substrates and proceed under similar conditions for both N-H and N-substituted hydroxylamines.
Stereochemistry of dimerisation of indole-3-acetic acid and its propyl ester
Fatum, Tine M.,Anthoni, Uffe,Christophersen, Carsten,Nielsen, Per Halfdan
, p. 784 - 789 (2007/10/03)
The mechanism, stereochemistry and products of the dimerisation of indole-3-acetic acid 1a and its propyl ester 1b in TFA and H3PO4 have been investigated. The major products in both acids were 2-(indolin-2-yl)indole dimers, 3a/b, which were readily converted into the corresponding pentacyclic lactams 5a/b with the pyrido[1,2-a:3,4-b′]biindole skeleton. Ccompound 5a was studied by X-ray crystallography and shown to be the 2,3-trans-isomer. The reaction proceeds via electrophilic attack of the protonated species 2 on free 1 with steric approach control to form the trans-stereoisomeric 3 and/or 5. Acta Chemica Scandinavica 1998.
