Quinolizidines. XVIII. Synthesis of (-)- and (+)-ankorines through a lactim ether route

概要

論文の詳細を見る
A formal chiral synthesis of the Alangium alkaloid (-)-ankorine [(-)-6] has been accomplished in the form of the synthesis of the lactam phenol (+)-14 from the (+)-trans-lactim ether (+)-5 and 2-benzyloxy-3,4-dimethoxyphenacyl bromide through the intermediates (+)-10 and 11. A parallel sequence of conversions starting from the (-)-trans-lactim ether (-)-5 and proceeding through the intermediates (-)-10,24,(-)-14,(-)-15,26,(+)-27,and (+)-28 produced the enantiomer [(+)-6] of natural ankorine. For an alternative chial synthesis of (-)-6,ethyl cincholoiponate [(+)-19] was acetylated and the resulting N-acetyl derivative (+)-20-was oxidized with RuO_4 to give the 6-piperidone (+)-21,and 2-piperidone (-)-23 in 55% and 27% yields, respectively. The (-)-cis-lactim ether (-)-16,obtained by ethylation of (+)-21 with triethyl-oxonium fluoroborate, was then converted into (-)-13,a known precursor for the synthesis of (-)-ankorine [(-)-6], in good overall yield by a "lactim ether route, " which proceeded through (+)-15 and 12.
公益社団法人日本薬学会の論文
1986-02-25