Total Synthesis of (−)-(6<i>S</i>,7<i>S</i>,8<i>S</i>,9<i>R</i>,10<i>S</i>,2‘<i>S</i>)-Membrenone-A and (−)-(6<i>S</i>,7<i>S</i>,8<i>S</i>,9<i>R</i>,10<i>S</i>)- Membrenone-B and Structural Assignment of Membrenone-C
作者:Rebecca A. Sampson、Michael V. Perkins
DOI:10.1021/ol025674o
日期:2002.5.1
[reaction: see text] (-)-(6S,7S,8S,9R,10S,2'S)-Membrenone-A and (-)-(6S,7S,8S,9R,10S)-membrenone-B were prepared in 11 steps (3% and 2.4% overall yield, respectively). Key steps included a tin(II)-mediated aldol followed by a syn selective reduction, giving the C7-C9 stereocenters, a second chain extending aldol coupling, and a p-TsOH-promoted cyclization/dehydration giving the common gamma-dihydropyrone
[反应:参见正文]制备了(-)-(6S,7S,8S,9R,10S,2'S)-Membrenone-A和(-)-(6S,7S,8S,9R,10S)-Membrenone-B 11个步骤(分别为3%和2.4%的总产率)。关键步骤包括锡(II)介导的羟醛,随后进行顺式选择性还原,得到C7-C9立体中心,第二条链延伸的羟醛偶联,以及p-TsOH促进的环化/脱水,得到普通的γ-二氢吡喃酮前体。因此,我们确定了合成的(-)-(6S,7S,8S,9R,10S,2'S)-甲基苯丙氨酸-A,(-)-(6S,7S,8S,9R,10S)-甲基苯丙胺-B,和( -)-(6S,7S,8S,9R,10S)-Mebrrenone-C是天然产物的对映异构体。