Date & Time: Feb 27 2025 | 11:10am - 12:10pm Location: iSTEM Building 2, Room 1218 Ring-closing alkyne metathesis (RCAM) has received considerable attention over the last 20 years for its utility in synthesizing macrocycles[1]. While its more widely studied counterpart—alkene metathesis—has become a cornerstone of modern synthetic methodology for macrocycle formation, alkyne metathesis remains comparatively unexplored[2]. However, recent studies have highlighted the synthetic potential of cycloalkynes as versatile intermediates for late-stage functionalization[3]. RCAM enables macrocyclization through an intramolecular alkyne metathesis reaction, effectively “stitching” two disubstituted alkynes together. This strategy was employed by the Fürstner group in 2016 in the total synthesis of Enigmazole A, leveraging RCAM to generate a functionalized cycloalkyne, followed by a gold-catalyzed [3,3]-sigmatropic rearrangement via an in situ-generated allene to construct a tetrahydropyran core[4]. Similarly, the Baran group utilized a cycloalkyne precursor for a one-pot gold-catalyzed skeletal rearrangement, yielding two tetrahydrofuran rings in the synthesis of Portimines A and B[5]. More recently, the Fürstner group applied RCAM in the total synthesis of (+)-Archangiumide, where a gold-catalyzed propargyl benzyl ether rearrangement facilitated the formation of an endocyclic allene[6]. This seminar will explore the rational design of alkyne metathesis catalysts and their application in total synthesis. The high functional group tolerance and chemoselectivity of these catalysts make RCAM a powerful tool for late stage macrocyclization and further derivatization. [1] Fürstner, A. J. Am. Chem Soc. 2021, 143, 15538-15555. [2] Cheng-Sánchez, I.; Sarabia, F. Synthesis2018, 50, 3749-3786. [3] Fürstner, A. Angew. Chem., Int. Ed. 2013, 52, 2794-2819. [4] Ahlers, A.; de Haro, T.; Gabor, B.; Fürstner, A. Angew. Chem., Int. Ed. 2016, 55, 1406-1411. [5] Tang, J.; Li, W.; Chiu, T. Y.; Martínez-Peña, F.; Luo, Z.; Chong, C. T.; Wei, Q.; Gazaniga, N.; West, T. J.; See, Y. Y.; Lairson, L. L.; Parker, C. G.; Baran, P. S. Nature, 2023, 622, 507-513. [6] Sutro, J. L.; Fürstner, A. J. Am. Chem. Soc. 2024, 146, 2345-2350. Type of Event: Organic Seminar Research Areas: Organic Chemistry Erick Lopez Department: Graduate Student, Department of Chemistry University of Georgia Learn more about the speaker https://chem.uga.edu/directory/people/erick-lopez
