C-H Functionalization: The Davies/Sorensen Synthesis of Aflatoxin B2
Shouyun Yu of Nanjing University devised a protocol for the distal dehydrogenation of the acyloxyamide 1 to the alkene 2 (Org. Lett. 2021, 23, 6931. ). Armido Studer of Westfalische Wilhelms-Universität reported related results (Chem. Eur. J. 2021, 27, 16621. ). M. Christina White of the University of Illinois achieved remarkable selectivity in the allylic amination of the protected brefeldin A (3), leading to 4 (J. Am. Chem. Soc. 2021, 143, 14969. ).
Yahong Li and Chen Zhu of Soochow University effected the oxidative rearrangment of the tertiary alcohol 5 to the aryl ketone 6 (Org. Chem. Front. 2021, 8, 6395. ). Tomislav Rovis of Columbia University assembled the ester 9 by adding cyclopentanone 7 to ethyl acrylate 8 (Synlett 2021, 32, 1767. ). Jin-Quan Yu of Scripps/La Jolla selectively carbonylated the methyl group of 10, to give the easily-differentiated anhydride 11 (Angew. Chem. Int. Ed. 2021, 60, 16382. ). Soon Hyeok Hong of KAIST converted sclareolide (12) to the equatorial nitrile 13 (Org. Lett. 2021, 23, 5501. ).
Stefan Bräse of the Karlsruhe Institute of Technology oxidized menthol (14) to the tetrahydrofuran 15 (Eur. J. Org. Chem. 2021, 3478. ). Professor Yu cyclized the amide 16 to the lactam 17 (J. Am. Chem. Soc. 2021, 143, 21657. ). Bert U. W. Maes of the University of Antwerp assembled the bridged pyrrolidine 20 by combining the amide 18 with the dibromide 19 (Angew. Chem. Int. Ed. 2021, 60, 21988. ). Takumi Furuta of Kyoto Pharmaceutical University achieved high ee in the cyclization of the α-aryl α-diazo ester 21 to the lactone 22 (ACS Catal. 2021, 11, 568. ).
Guozhu Zhang of the Shanghai Institute of Organic Chemistry constructed the cyclobutanol 25 by adding the iodomethyl silane 24 to the alkyne 23 (Nature Commun. 2021, 12, 6404. ). X. Peter Zhang of Boston College used a Co catalyst to cyclize the α-aryl α-diazo ketone 26 to the cyclobutanone 27 (J. Am. Chem. Soc. 2021, 143, 11670. ).
The aflatoxins, exemplified by aflatoxin B2 (31), are a family of dangerous liver carcinogens produced by Aspergillus fungi. Huw M. L. Davies of Emory University and Erik J. Sorensen of Princeton University established the key stereogenic center of 31 by the enantioselective insertion of the α-aryl α-diazo ester 28 into the methyl group of the alkene 29 to give 30 (Org. Lett. 2021, 23, 9393. ).