489-54-3Relevant articles and documents
A Two-Directional Synthesis of (+)-β-Isosparteine
Al-Saffar, Firas M.,Brown, Richard C. D.
, p. 3502 - 3504 (2017)
A two-directional synthesis of (+)-β-isosparteine is described in five steps from glutaric acid, where the entire carbon and nitrogen backbone of the alkaloid, possessing the requisite relative and absolute stereochemistry at its four stereogenic centers, is assembled using a double imino-aldol reaction.
Total synthesis of (±)-α-isosparteine, (±)-β- isosparteine, and (±)-sparteine from a common tetraoxobispidine intermediate
Norcross, Neil R.,Melbardis, John P.,Solera, Margarita Ferris,Sephton, Mark A.,Kilner, Colin,Zakharov, Lev N.,Astles, Peter C.,Warriner, Stuart L.,Blakemore, Paul R.
, p. 7939 - 7951 (2008/12/23)
(Chemical Equation Presented) The three title alkaloids were separately prepared in stereocontrolled fashion from a common tetraoxobispidine precursor, 3,7-diallyl-2,4,6,8-tetraoxo-3,7-diazabicyclo[3.3.1]nonane (16). Bisimide 16 was generated from malonate via acid promoted cyclization of the Knoevenagel condensation adduct 1,1,3,3-propanetetracarboxamide. (±)-α- Isosparteine (dl-2) was elaborated from 16 in 28% overall yield by a two-directional synthetic sequence composed of four reactions: double addition of allylmagnesium bromide, ring-closing olefin metathesis (RCM), hydrogenation, and borane mediated reduction. (±)-β-Isosparteine (dl-3) was targeted along similar lines by a strategic reversal in allylation and reduction operations on the core synthon. Thus, 16 was advanced to dl-3 in five steps and 12% overall yield by a reaction sequence commencing with sodium borohydride mediated reduction and followed by double Sakurai-type allylation of the resulting bishemiaminal. The synthesis of dl-3 was concluded by RCM and then global reduction (H2, Pd/C; LiAlH4). The final target, (±)-sparteine (dl-1), was secured in six steps and 11% overall yield from 16 by monoreduction and Sakurai allylation, followed by allyl Grignard addition and then RCM and global reduction as before. Reasons for the inherent C 2-type regioselectivity of net double nucleophilic additions to tetraoxobispidines are discussed and enantioselective oxazaborolidine mediated reduction of the N,N′-dibenzyl congener of 16 is reported.
Concise asymmetric synthesis of (-)-sparteine
Hermet, Jean-Paul R.,McGrath, Matthew J.,O'Brien, Peter,Porter, David W.,Gilday, John
, p. 1830 - 1831 (2007/10/03)
A six-step asymmetric synthesis of natural (-)-sparteine from ethyl 7-iodohept-2-enoate is reported, involving a connective Michael addition of an amino ester-derived enolate to an α,β-unsaturated amino ester.
