Carbon-Carbon Bond Formation: The Lee Synthesis of Erinacerin A
Ruben Martin of ICIQ established (Nature 2017, 545, 84. DOI: 10.1038/nature22316) a procedure for the equilibrating carboxylation of any of the bromides represented by 1 to the linear carboxylic acid 2. The net transformation, random monobromination followed by carboxylation, converts the terminal C-H of a hydrocarbon to the one-carbon linear acid. Matthias Beller of the Leibniz-Institut für Katalyse described (Angew. Chem. Int. Ed. 2017, 56, 6203. DOI: 10.1002/anie.201701950) a complementary procedure for converting branched tertiary alcohols to linear esters (not illustrated).
Hongjian Lu of Nanjing University devised (J. Org. Chem. 2017, 82, 4677. DOI: 10.1021/acs.joc.7b00308) a linchpin protocol for linking two alkyl groups, forming 4 by gently warming the sulfamoyl azide 3. Cristina Nevado of the University of Zurich effected (J. Am. Chem. Soc. 2017, 139, 6835. DOI: 10.1021/jacs.7b03195) the bis alkylation of a terminal alkene, coupling 6 with 5 and t-butyl iodide to make 7. Samir Z. Zard of the École Polytechnique showed (Org. Lett. 2017, 19, 1866. DOI: 10.1021/acs.orglett.7b00627) that the initial product from the radical addition of 9 to 8, followed by cyclization, could be coupled with 10 to give 11 with high stereocontrol.
Tobias Ritter of the Max-Planck-Institut für Kohlenforschung used (J. Am. Chem. Soc. 2017, 139, 7184. DOI: 10.1021/jacs.7b03749) acetone cyanohydrin 13 to effect the hydrocyanation of the alkyne 12 to the nitrile 14. Mathieu Sauthier of the University of Lille prepared (Angew. Chem. Int. Ed. 2017, 56, 7460. DOI: 10.1002/anie.201703486) the aldehyde 17 by coupling the aldehyde 15 with allyl alcohol 16. Varinder K. Aggarwal of the University of Bristol optimized (Angew. Chem. Int. Ed. 2017, 56, 786, DOI: 10.1002/anie.201610387; Org. Lett. 2017, 19, 2762, DOI: 10.1021/acs.orglett.7b01124) the assembly of 20 by coupling 19 with 18. Phil S. Baran of Scripps/La Jolla reported (Nature 2017, 545, 213. DOI: 10.1038/nature22307) the decarboxylative coupling of 21 with 22 to give 23.
Bruce D. Hammock of the University of California, Davis alkylated (Org. Biomol. Chem. 2017, 15, 4308. DOI: 10.1039/C7OB00789B) the alkyne 24 with the triflate 25 to give 26. Liqun Jin and Xinquan Hu of the Zhejiang University of Technology found (Chem. Commun. 2017, 53, 4124. DOI: 10.1039/C7CC00891K) that catalytic Cu could improve such alkylations. Salvatore D. Lepore of Florida Atlantic University assembled (Chem. Commun. 2017, 53, 5125. DOI: 10.1039/C7CC01708A) the alkyne 29 by displacing the allylic bromide 27 with 28.
Claude Spino of the Université de Sherbrooke followed (Heterocycles 2017, 95, 894. DOI: 10.3987/COM-16-S(S)58) Shi epoxidation of 30 with cuprate displacement with 31 to prepare the allene 32. Regan J. Thomson of Northwestern University and Scott E. Schaus of Boston University prepared (J. Am. Chem. Soc. 2017, 139, 1998. DOI: 10.1021/jacs.6b11937) the allene 35 by way of an organocatalyzed Petasis coupling of 34 with the sulfonylhydrazone derived from 33.
Erinacerin A (39), isolated from the edible mushroom Hericium erinaceum, showed activity against SK-MEL-2 cells. En route to 39, Yunmi Lee of Kwangwoon University developed (J. Org. Chem. 2017, 82, 6349. DOI: 10.1021/acs.joc.7b00920) an improved protocol for the geometrically-controlled borylative alkylation that converted 36 to 37, ready to be coupled with 38.