Midya Abhisek, Khalse Laxman Devidas, Ghorai Prasanta
Department of Chemistry, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal By-pass Road, Bhauri, Bhopal, 462066, India.
Chemistry. 2023 Oct 23;29(59):e202301563. doi: 10.1002/chem.202301563. Epub 2023 Sep 18.
An unprecedented enantioselective organocatalytic spirocyclization strategy is presented by in situ generation of aminoisobezofulvenes. The reaction sequence involves a reductive Michael/aldol-condensation/Michael addition cascade by iminium-enamine catalysis. The key success of this spirocyclization was the formation of intermediatory nucleophilic aminoisobenzofuvenes accountable for intramolecular Michael addition. Benzospirononanes featuring an all carbon qauternary spirocenter were obtained using proline-derived amino-organocatalyst in moderate to good yields and excellent diastereo- and enantioselectivities (up to >20 : 1 dr, and 99 % ee). Post-methodological manipulation of benzospirononanes was also demonstrated.
通过原位生成氨基异苯并富烯，提出了一种前所未有的对映选择性有机催化螺环化策略。该反应序列涉及亚胺离子-烯胺催化的还原迈克尔/羟醛缩合/迈克尔加成串联反应。这种螺环化的关键成功之处在于形成了负责分子内迈克尔加成的中间体亲核氨基异苯并富烯。使用脯氨酸衍生的氨基有机催化剂以中等至良好的产率以及优异的非对映和对映选择性（高达>20:1的非对映体比例和99%的对映体过量）获得了具有全碳季碳螺中心的苯并螺壬烷。还展示了苯并螺壬烷的后方法学操作。
