Catalytic Asymmetric Total Syntheses of Naturally Occurring <i>Amarylidaceae</i> Alkaloids, (−)-Crinine, (−)-<i>epi</i>-Crinine, (−)-Oxocrinine, (+)-<i>epi</i>-Elwesine, (+)-Vittatine, and (+)-<i>epi</i>-Vittatine*
作者:Mrinal K. Das、Nivesh Kumar、Alakesh Bisai
DOI:10.1021/acs.orglett.8b01703
日期:2018.8.3
(−)-oxocrinine (1f), and (−)-buphanisine (1d) have been accomplished. Gratifyingly, naturally occurring Amaryllidaceae alkaloids such as (+)-vittatine (1g), (+)-epi-vittatine (1h), and (+)-epi-elwesine (1i) [enantiomers of (−)-1c, (−)-1e, and (−)-1b, respectively] have also been achieved by switching the antipode of ligand used in the catalytic enantioselective step.
迅速的方法来crinine型的对映选择性催化全合成石蒜生物碱具有通过Pd催化的对映选择性脱羧allylenol碳酸盐的烯丙基化的关键步骤(高达96%ee)的而完成的。使用这种策略,集体全合成石蒜生物碱如( - ) -外延-elwesine(1B),( - ) - crinine(1C),( - ) -外延-crinine(1E),( - ) - oxocrinine(1F)和(-)-buphanisine(1d)已完成。令人欣慰的是,天然存在的金莲花科生物碱,例如(+)-vittatine(1g),(+)-Epi -vittatine(1h)和(+)- epi -elwesine(1i)[分别是(-)- 1c,(-)- 1e和(-)- 1b的对映体]也可以通过切换对映体来实现催化对映选择性步骤中使用的配体的数量。