Oxidation: The Baran Synthesis of Nookatone
Ian R. Baxendale of the University of Durham devised (Tetrahedron 2016, 72, 2947. DOI: 10.1016/j.tet.2016.04.011) a protocol for converting the enol acetate of the ketone 1 to the enone 2. Hideo Togo of Chiba University effected (Eur. J. Org. Chem. 2016, 768. DOI: 10.1002/ejoc.201501315) the oxidative decarboxylation of the acid 4 to the imide 5. Hua Fu of Tsinghua University described (Org. Lett. 2016, 18, 1968. DOI: 10.1021/acs.orglett.6b00489) the related conversion of a carboxylic acid to the selenide, and Jinxing Ye of the East China University of Science and Technology reported (Chem. Commun. 2015, 51, 11864. DOI: 10.1039/C5CC04527D) an improved procedure for decarboxylative fluorination. Brian M. Cochran of Amgen optimized (Synlett 2016, 27, 245. DOI: 10.1055/s-0035-1560659) the oxidative cleavage of the alkene 6 to the carboxylic acid 7. Takayuki Yakura of the University of Toyama used (Adv. Synth. Catal. 2016, 358, 869. DOI: 10.1002/adsc.201500795) oxone in the presence of a catalytic amount of 9 to convert 8 to the lactone 10.
Sundarababu Baskaran of the Indian Institute of Technology Madras selectively oxidized (Chem. Eur. J. 2016, 22, 902. DOI: 10.1002/chem.201503998) the benzylidene acetal 11 to the acid 12. Vladimir Gevorgyan of the University of Illinois, Chicago used (J. Am. Chem. Soc. 2016, 138, 6340. DOI: 10.1021/jacs.6b01628) photolysis to promote the Pd-mediated conversion of 13 to 14. Related transformations were reported by Catellani ( 2008, December 8) and by Doucet ( 2015, March 16).
Christoforos G. Kokotos of the National and Kapodestrian University of Athens employed (Chem. Eur. J. 2016, 22, 6964. DOI: 10.1002/chem.201600333) the keto acid 16 as a photocatalyst for the conversion of 15 to the hydroxamic acid 17. Olof Ramström and Mingdi Yan of KTH - Royal Institute of Technology found (Chem. Sci. 2016, 7, 713. DOI: 10.1039/C5SC03510D) that under alkaline conditions in DMSO, an aldehyde 18 could be coupled with an aryl azide 19 to construct the anilide 20.
Timothy R. Newhouse of Yale University showed (J. Am. Chem. Soc. 2016, 138, 1166. DOI: 10.1021/jacs.5b12924) that with 23 as the oxidant, the zinc enolate of lactam 21, prepared by exposure to 22 followed by zinc chloride, could be converted to 24. Yan-Biao Kang of the University of Science and Technology of China effected (Org. Lett. 2016, 18, 228. DOI: 10.1021/acs.orglett.5b03367) the oxidative decarbonylation of 25 to the nitrile 26. Ning Jiao of Peking University rearranged (Synthesis 2015, 47, 2971. DOI: 10.1055/s-0034-1380222) the benzylic azide 27 to the amide 28. Professor Jiao also elaborated (Chem. Sci. 2015, 6, 6355. DOI: 10.1039/C5SC02126J) the terminal alkyne 29 to the unsaturated nitrile 30.
Robert Todd of Aldrich and Liming Zhang of the University of California, Santa Barbara developed (Adv. Synth. Catal. 2016, 358, 1417. DOI: 10.1002/adsc.201600027) the N-oxide 32 to mediate the iodination of the alkyne 31 to the enone 33. Phil S. Baran of Scripps, La Jolla found (Nature 2016, 533, 77. DOI: 10.1038/nature17431) that 35 effectively promoted the electrolytic oxidation of the inexpensive hydrocarbon valencene (34) to the valuable flavor component nootkatone (36).