Studies of the Strategic Syntheses of Natural Products with Contiguous All-Carbon Quaternary Stereocenters

The synthetic studies toward natural products with contiguous all-carbon quaternary stereocenters, including waihoensene and bipolarolides A-D are described. By regarding the quaternary centers as key structural elements and carefully analyzing the challenges and opportunities related to them, synthetic routes were designed in a concise and reliable manner. In particular, gold-catalyzed cyclization reactions were found to be exceptionally powerful in the construction of contiguous quaternary centers. A tandem gold(I)-catalyzed cyclization reaction to form angular tricyclic structures with three contiguous quaternary centers was discovered and further evaluated in the syntheses of complex natural products. A thorough literature review of the applications of gold(I)-catalysis in the formation of all-carbon quaternary centers is also included, with our novel insight of the importance of the linear nature of gold(I)-complexes in such transformations.