83196-13-8Relevant academic research and scientific papers
Synthesis Applications of Cationic Aza-Cope Rearrangements. Stereoselective synthesis of cis- and trans-3a-Aryl-4-oxodecahydrocycloheptapyrroles
Overman, Larry E.,Jacobsen E. Jon,Doedens, Robert J.
, p. 3393 - 3400 (2007/10/02)
A general synthesis of 3a-aryl-4-oxodecahydrocycloheptapyrroles is detailed (eq 1, n=2).The key step is a "ring-enlarging pyrrolidine annulation" reaction which occurs when 2-amino-1-(1-arylvinyl)cyclohexanols are treated at 25-80 deg C with an aldehyde and acid.Three different methods (Schemes I and II) for assembling the 2-amino-1-(1-arylvinyl)cyclohexanol intermediates are reported. cis-3a-Aryl-4-oxodecahydrocycloheptapyrroles can be formed with complete stereocontrol from either cis- or trans-2-amino-1-(1-arylvinyl)cyclohexanols.The corresponding trans bicyclics can be prepared with modest (ca. 3:1) selectivity from cis-2--1-(1-arylvinyl)cyclohexanols.The stereochemical outcome of these tandem cationic aza-Cope-Mannich cyclization reactions is consistent with chair topographies for the rearrangment steps (Scheme III).
THE CYANOMETHYL GROUP FOR NITROGEN PROTECTION AND IMINIUM ION GENERATION IN RING-ENLARGING PYRROLIDINE ANNULATIONS. A SHORT SYNTHESIS OF THE AMARYLLIDACEAE ALKALOID d,1-CRININE
Overman, Larry E.,Jacobsen, E. Jon
, p. 2741 - 2744 (2007/10/02)
The preparation of cis-3a-aryl-4-oxo-decahydrocycloheptapyrroles and cis-3a-aryl-4-oxo-octahydroindoles is faciliated by using a cyanomethyl group to both protect nitrogen and serve as a precursor for a formaldehyde iminium ion.
