Studies towards the total synthesis of mumbaistatin: synthesis of highly substituted benzophenone and anthraquinone building blocks
摘要:
Model compounds and building blocks for a planned total synthesis of the highly potent glucose-6-phosphate (G6P) translocase inhibitor mumbaistatin (1) and structural analogs were elaborated: compound 1 represents a lead structure in the development of potential new antidiabetic drugs. With the model substrate 20 it was demonstrated that highly functionalized, tetra-ortho-substituted benzophenones can be prepared by nucleophilic addition of an aryllithium-building block to a benzaldehyde followed by oxidation. For compound 37, a potential precursor of the anthraquinone part of mumbaistatin, various approaches via aryne/phthalide annulations were developed and evaluated. The required functionalized arenes were prepared exploiting, among others, regioselective bromination and ortho-lithiation reactions. Coupling reactions of the anthracene-carbaldehyde 44 derived from 37 with various metalated arenes proved to be unexpectedly difficult and failed so far. (C) 2003 Elsevier Science Ltd. All rights reserved.
Carbene-Catalyzed Formal [5 + 5] Reaction for Coumarin Construction and Total Synthesis of Defucogilvocarcins
作者:Xuan Huang、Tingshun Zhu、Zhijian Huang、Yuexia Zhang、Zhichao Jin、Giuseppe Zanoni、Yonggui Robin Chi
DOI:10.1021/acs.orglett.7b03102
日期:2017.11.17
An N-heterocyclic carbene-catalyzed formal [5 + 5] reaction between enals and furanones that generates multisubstituted coumarins in a single step is reported. Five atoms in each of the substrates are involved in this catalytic process to form a benzene and a lactone ring. The power of the method is further demonstrated in metal-free total syntheses of several natural products (defucogilvocarcins M