Enantioselective Total Syntheses of Welwitindolinone A and Fischerindoles I and G
摘要:
The first total syntheses of welwitindolinone A and the most complex members of the fischerindole family, fischerindoles I and G, are reported. Highlights of these short, protecting-group-free syntheses include the application of the recently developed direct indole-carbonyl coupling, a simple approach for installing the quaternary center with neighboring chlorine atom, a regioselective dehydrogenation/dehydration cascade to access fischerindole I, and a remarkably facile oxidative ring contraction to construct welwitindolinone A. An alternative biogenetic hypothesis, whose accuracy is suggested by the success of the current syntheses, is also put forth for this alkaloid family.
Scope and Mechanism of Direct Indole and Pyrrole Couplings Adjacent to Carbonyl Compounds: Total Synthesis of Acremoauxin A and Oxazinin 3
作者:Jeremy M. Richter、Brandon W. Whitefield、Thomas J. Maimone、David W. Lin、M. Pilar Castroviejo、Phil S. Baran
DOI:10.1021/ja074392m
日期:2007.10.1
Full details are provided for a recently invented method to couple indoles and pyrroles to carbonyl compounds. The reaction is ideally suited for structurally complex substrates and exhibits high levels of chemoselectivity (functional group tolerability), regioselectivity (coupling occurs exclusively at C-3 of indole or C-2 of pyrrole), stereoselectivity (substrate control), and practicality (amenable
提供了最近发明的将吲哚和吡咯与羰基化合物偶联的方法的全部细节。该反应非常适合结构复杂的底物,并表现出高水平的化学选择性(官能团耐受性)、区域选择性(偶联仅发生在吲哚的 C-3 或吡咯的 C-2)、立体选择性(底物控制)和实用性(适合)以扩大规模)。此外,四元立构中心很容易且可预测地生成。该反应已应用于许多合成问题,包括天然产物 hapalindole 家族成员、酮咯酸、acremoauxin A 和恶嗪宁 3 的全合成。从机理上讲,该偶联方案似乎通过需要生成的单一电子转移过程来操作与羰基相邻的缺电子自由基,然后被吲哚或吡咯阴离子拦截。
Enantiospecific Total Synthesis of the Hapalindoles, Fischerindoles, and Welwitindolinones <i>via</i> a Redox Economic Approach
作者:Jeremy M. Richter、Yoshihiro Ishihara、Takeshi Masuda、Brandon W. Whitefield、Tomás Llamas、Antti Pohjakallio、Phil S. Baran
DOI:10.1021/ja806981k
日期:2008.12.31
the total synthesis of several members of the hapalindole family of naturalproducts, including hapalindole Q, 12-epi-hapalindole D, 12-epi-fischerindole U, 12-epi-fischerindole G, 12-epi-fischerindole I, and welwitindolinone A. Use of the recently developed direct indole coupling enabled an efficient, practical, scalable, and protecting-group-free synthesis of each of these naturalproducts. The original
提供了天然产物 hapalindole 家族几个成员的全合成的完整细节,包括 hapalindole Q、12-epi-hapalindole D、12-epi-fischerindole U、12-epi-fischerindole G、12-epi-fischerindole I , 和 welwitindolinone A. 使用最近开发的直接吲哚偶联能够高效、实用、可扩展且无保护基团合成这些天然产物中的每一种。审查了最初的生物合成提案,并提出了修改后的生物合成假设,并通过上述合成进行了验证。合成的特征还在于坚持“氧化还原经济”的概念。类似于“原子经济”或“阶梯经济”,“氧化还原经济”最大限度地减少了合成中多余的氧化还原操作;相当,
Enantioselective Total Syntheses of Welwitindolinone A and Fischerindoles I and G
作者:Phil S. Baran、Jeremy M. Richter
DOI:10.1021/ja056171r
日期:2005.11.1
The first total syntheses of welwitindolinone A and the most complex members of the fischerindole family, fischerindoles I and G, are reported. Highlights of these short, protecting-group-free syntheses include the application of the recently developed direct indole-carbonyl coupling, a simple approach for installing the quaternary center with neighboring chlorine atom, a regioselective dehydrogenation/dehydration cascade to access fischerindole I, and a remarkably facile oxidative ring contraction to construct welwitindolinone A. An alternative biogenetic hypothesis, whose accuracy is suggested by the success of the current syntheses, is also put forth for this alkaloid family.