Research Interests
Professor Yang’s research group is concerned with two areas: (1) the total synthesis of complex natural products, in particular those with important bioactivity and fascinating structure; and (2) the development of new methods and strategies in synthetic organic chemistry, including the applications of asymmetric catalysis for total synthesis.
Very recently, we have developed a new enantioselective indole cyclization strategy for the asymmetric synthesis of akuammiline alkaloids. The cyclization reaction employs the combination of Lewis acid activation with an iridium catalyst and a Carreira ligand, and readily accessible 2,3-disubstituted indoles with C-2 racemic secondary allylic alcohols and C-3 heteroatoms. Based on this reaction, the first asymmetric total synthesis including the assignment of the absolute configuration of (-)-aspidophylline A has been achieved (Angew. Chem. Int. Ed. 2016, DOI: 10.1021/anie.201511549).
We also report a concise and highly enantioselective total synthesis of (-)-alstoscholarisine A, a recently isolated monoterpenoid indole alkaloid that has significant bioactivity in promoting adult neuronal stem cells proliferation. A highly enantioselective (99% ee), intramolecular Ir-catalyzed Friedel-Crafts alkylation of indole with a secondary allylic alcohol was utilized to establish the first stereogenic center upon which the other three contiguous chiral centers were readily set by a highly stereoselective tandem 1,4-addition and aldol reaction. The key tetrahydropyran was constructed through a hemiacetal reduction, and the final aminal bridge was forged by a one-pot reductive amination/cyclization. The conciseness of this approach was highlighted by building core bonds in each step with a minimalist protecting group strategy (J. Am. Chem. Soc. 2016, DOI: 10.1021/jacs.6b00625).