A method has been developed to assign the absolute configuration and enantiomeric excess of anabasine based on small amounts of material (in the microgram range), by derivatization with (+)-menthylchloroformate followed by capillary GC analysis of the resulting carbamate(s). This method was applied to three samples of anabasine isolated from Messor and Aphaenogaster ants. In Messor sanctus, only (2'S)-anabasine was present, whereas in Aphaenogaster subterranea and A. miamiana (2'S)-anabasine was determined to have an ee of 78 and 24%, respectively.
Asymmetric aza-Diels-Alder reaction: enantio- and diastereoselective reaction of imine mediated by Chiral Lewis acid
作者:Kouji Hattori、Hisashi Yamamoto
DOI:10.1016/s0040-4020(01)80532-9
日期:1993.2
asymmetric aza-Diels-Alder reaction usingchiral boron mediator is developed. The key to its success is the use of the chiral boron complex prepared in situ from (R)- or (S)- binaphthol and B(OPh)3. The enantiomeric reaction of prochiral imine affords products of up to 90% ee. The double asymmetric induction of chiral imine using α-benzylamine as a chiralauxiliary is achieved with almost complete diastereoselectivity
A Straightforward Synthesis of (S)-Anabasine via the Catalytic, Enantioselective Vinylogous Mukaiyama-Mannich Reaction
作者:Christoph Schneider、David Giera、Marcel Sickert
DOI:10.1055/s-0029-1217026
日期:2009.11
The tobacco alkaloid (S)-anabasine was synthesized by a straightforward 4-step sequence with the catalytic enantioselective vinylogous Mannich reaction as a key step. Only 3 mol% of a structurally optimized chiral BINOL-based phosphoric acid was employed to control the absolute configuration of the natural product.