Beshore Douglas C, Smith Amos B
Department of Chemistry, Laboratory for Research on the Structure of Matter, and Monell Chemical Senses Center, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
J Am Chem Soc. 2008 Oct 15;130(41):13778-89. doi: 10.1021/ja804939r. Epub 2008 Sep 18.
A full account of the enantioselective total syntheses of (+)-lyconadin A (1) and (-)-lyconadin B (2) is presented. Central to this venture was recognition and deployment of a key strategy-level intramolecular aldol/conjugate addition cascade that led, in a single operation, to two new carbon-carbon sigma-bonds, three new stereogenic centers, and two new rings, albeit with the incorrect stereogenicity at C(12) for the lyconadins. Correction of the C(12) stereogenicity was achieved via innovative use of a protonated intramolecular aminal. An aminoiodo olefin cyclization, in conjunction with alpha-pyridinone and 3,4-dihydropyridinone annulation protocols, permitted completion of the syntheses of (+)-lyconadin A (1) and (-)-lyconadin B (2), respectively.
本文详细介绍了(+)-lyconadin A（1）和(-)-lyconadin B（2）的对映选择性全合成。这一研究的核心是识别并运用一种关键的策略级分子内羟醛/共轭加成串联反应，该反应在一次操作中形成了两个新的碳-碳σ键、三个新的立体中心和两个新的环，尽管lyconadins在C(12)处的立体化学构型不正确。通过创新性地使用质子化分子内亚胺，实现了C(12)立体化学构型的校正。氨基碘代烯烃环化反应与α-吡啶酮和3,4-二氢吡啶酮环合方案相结合，分别完成了(+)-lyconadin A（1）和(-)-lyconadin B（2）的合成。
