C-H Functionalization: The Inoue Synthesis of Zaragozic Acid C
Jennifer M. Schomaker of the University of Wisconsin found (Chem. Commun. 2017, 53, 4346. DOI: 10.1039/C7CC01235G) that silver catalysts selectively directed the cyclization of 1 to H1, to give 2. Other catalysts (Rh, Mn, Ru) directed the cyclization to H2. Tian-Sheng Mei of the Shanghai Institute of Organic Chemistry used (J. Am. Chem. Soc. 2017, 139, 3293. DOI: 10.1021/jacs.7b01232) Pd-catalyzed electrochemical oxidation to convert 3 to 4. Phil S. Baran of Scripps/La Jolla showed (J. Am. Chem. Soc. 2017, 139, 7448. DOI: 10.1021/jacs.7b03539) that scalable electrochemical oxidation selectively converted 5 into cyclohexanone 6. Andrey P. Antonchick of the Max-Planck-Institut Dortmund oxidized (Chem. Sci. 2017, 8, 452. DOI: 10.1039/C6SC03055F) the hydrocarbon 7 to the diol 8.
In an elegant illustration of intramolecular hydride abstraction, Xiaoan Wen and Guangji Wang of China Pharmaceutical University prepared (Org. Lett. 2017, 19, 1566. DOI: 10.1021/acs.orglett.7b00378) the amide 11 by coupling 9 with TosMIC (10). Carvone has been the starting material for many enantioselective target-directed syntheses. Junbiao Chang of Henan Normal University and Xingwei Li of the Dalian Institute of Chemical Physics significantly extended the utility of carvone, adding (Org. Lett. 2017, 19, 2086. DOI: 10.1021/acs.orglett.7b00690) 12 to acrolein 13 to give 14. Hosea M. Nelson of UCLA directly arylated (Science 2017, 355, 1403. DOI: 10.1126/science.aam7975) the hydrocarbon 15 with the phenyl cation derived from 16 to selectively give the terminal product 17. Guangbin Dong of the University of Chicago converted (J. Am. Chem. Soc. 2017, 139, 5716. DOI: 10.1021/jacs.7b02020) the mixture of alkenes resulting from the regioselective addition of 18 to 19 into the single alcohol 20.
Wenjun Lu of Shanghai Jiao Tong University cyclized (Org. Lett. 2017, 19, 1768. DOI: 10.1021/acs.orglett.7b00536) the amide 22 to the β-lactam 23. Olivier Baudoin of the University of Basel described (Angew. Chem. Int. Ed. 2017, 56, 7218. DOI: 10.1002/anie.201703109) a complementary route to β-lactams (not illustrated). Masahiro Anada and Shunichi Hashimoto of Hokkaido University observed (Heterocycles 2017, 95, 1211. DOI: 10.3987/COM-16-S(S)72) substantial enantioselectivity in the cyclization of the prochiral 24 to 25.
Chunquan Sheng of the Second Military Medical University and Yu Rao of Tsinghua University devised (Chem. Commun. 2017, 53, 1534. DOI: 10.1039/C6CC06897A) a double distal activation, coupling 26 with the enone 27 to give cyclobutane 28. Anita R. Maguire of University College Cork cyclized (Org. Biomol. Chem. 2017, 15, 2609. DOI: 10.1039/C7OB00214A) 29 to cyclopentanone 30 in high ee.
Zaragozic acid C (33), isolated from the fungus Leptodontidium elatius, is a potent inhibitor of mammalian squalene synthase. En route to 33, Masayuki Inoue of the University of Tokyo cyclized (J. Am. Chem. Soc. 2017, 139, 1814. DOI: 10.1021/jacs.6b13263) the α-diketone 31 to 32.