C-H Functionalization: The Snyder Synthesis of Scaparvin B
Michael K. Hilinski of the University of Virginia found that the ketone 2 could be used catalytically to mediate the selective hydroxylation of 1 to 3 (Org. Lett. 2017, 19, 4790. ). David A. Nagib of Ohio State University showed that oxidation followed by aqueous hydrolysis converted the imidate 4 to the amino alcohol 5 (J. Am. Chem. Soc. 2017, 139, 10204. ).
Soon Hyeok Hong of Seoul National University found that under photostimulation, the ether 6 could be carbonylated with 7 to give 8 (Chem. Sci. 2017, 8, 6613. ). Naoya Kumagai and Masakatsu Shibasaki of the Institute of Microbial Chemistry also used photostimulation to promote the acylation of 9 with 10, leading to 11 (Org. Lett. 2017, 19, 3727. ). Tomislav Rovis of Columbia University showed that photostimulation alone was sufficient to promote the alkylation of 12 with 13 to give 14 (J. Am. Chem. Soc. 2017, 139, 14897. ). Huw M. L. Davies of Emory University designed a Rh catalyst that mediated the selective and enantioselective alkylation of 15 with 16 to give 17 (Nature 2017, 551, 609. ).
Christopher J. Moody of the University of Nottingham also used a Rh catalyst to cyclize 18 to the β-lactone 19 (Chem. Eur. J. 2017, 23, 13623. ). John R. Falck of the University of Texas Southwestern Medical Center showed that depending on the choice of Rh catalyst, 20 could be cyclized selectively to either diastereomer of 21 (J. Am. Chem. Soc. 2017, 139, 18288. ). Matthew J. Gaunt of the University of Cambridge assembled the β-lactam 23 by carbonylating 22 (Chem. Sci. 2017, 8, 8198. ). In a process that probably involves intramolecular hydride abstraction, Shoko Yamazaki of the Nara University of Education cyclized 24 to 25 (J. Org. Chem. 2017, 82, 6748. ).
Yandong Zhang of Xiamen University observed that the Rh-mediated cyclization of 26 led predominantly to 27 (Angew. Chem. Int. Ed. 2017, 56, 8187. ). Jeremy A. May of the University of Houston designed a Rh catalyst that cyclized the prochiral 29 to 30 in high ee (ACS Catal. 2017, 7, 6155. ).
Selective C-H insertion can be a powerful tool for rapidly increasing molecular complexity. This is well illustrated by the conversion of 31 to 32, reported by Scott A. Snyder of the University of Chicago in the course of a synthesis of scaparvin B (33) (J. Am. Chem. Soc. 2017, 139, 18428. ).