Oxidation of Organic Functional Groups: The Metz Synthesis of (+)-Orientalol F
Frank Glorius of the Westfälische-Wilhelms-Universität Münster showed (Chem. Eur. J. 2016, 22, 9971. DOI: 10.1002/chem.201602251) that under irradiation, 2 served as an effective donor for the decarboxylative bromination of 1 to 3. Vidar R. Jensen of the University of Bergen developed (ACS Catal. 2016, 6, 7784. DOI: 10.1021/acscatal.6b02460) a Pd-mediated protocol for the decarboxylation of 4 to 5. Kurt Faber of the University of Graz developed (Eur. J. Org. Chem. 2016, 3473. DOI: 10.1002/ejoc.201600358) a related enzymatic decarboxylation.
Several useful oxidative fragmentations have been reported. Martin J. Lear of the University of Lincoln and Yujiro Hayashi of Tohoku University established (Angew. Chem. Int. Ed. 2016, 55, 9060. DOI: 10.1002/anie.201603399) that a malononitrile 6 could be coupled with the amine 7 to give the amide 8. Xiaoguang Bao and Chen Zhu of Soochow University effected (Org. Chem. Front. 2016, 3, 227, 1467. DOI: 10.1039/C5QO00368G,) the chlorinative cleavage of cyclobutanol 9 to 10. Zhiwei Zuo of ShanghaiTech University observed (Angew. Chem. Int. Ed. 2016, 55, 15319. DOI: 10.1002/anie.201609035) that the intermediate from cleavage of 11 could be trapped with 12 to give 13. Zhan Lu of Zhejiang University accomplished (Chem. Eur. J. 2016, 22, 17566. DOI: 10.1002/chem.201604440) the oxidative conversion of the cis amine 15 to 16.
Aiwen Lei of Wuhan University devised (J. Am. Chem. Soc. 2016, 138, 12037. DOI: 10.1021/jacs.6b07411) a Co-mediated conversion of the styrene 17 to the α-aryl ketone 18. Chao-Jun Li of McGill University uncovered (Angew. Chem. Int. Ed. 2016, 55, 10806. DOI: 10.1002/anie.201604847) catalytic conditions for the otherwise very challenging oxidation of 19 to carboxylic acid 20. Timothy R. Newhouse of Yale University improved (Org. Biomol. Chem. 2016, 14, 6197. DOI: 10.1039/C6OB00941G) the Org. Syn. (DOI: 10.15227/orgsyn.082.0108) procedure for the fragmentation of the hydroperoxide derived from 21 to give the enone 22. Nicholas E. Leadbeater of the University of Connecticut demonstrated (Synlett 2016, 27, 2372. DOI: 10.1055/s-0035-1561498) that the oxoammonium salt 24 could oxidize the silyl ether 23 directly to the aldehyde 25.
Oxidation usually has required a stoichiometric reagent. Derya Gülcemal and Jianliang Xiao of the University of Liverpool designed (Chem. Eur. J. 2016, 22, 10513. DOI: 10.1002/chem.201601648) an Ir catalyst that converted alcohol 26 to ketone 27 with the release of H2. Similarly, H2 was the byproduct in the Rh-catalyzed oxidative esterification of 28 to 29 reported (Chem. Sci. 2016, 7, 4428. DOI: 10.1039/C6SC00145A) by Professor Xiao and Chao Wang of Shaanxi Normal University.
In the course of a synthesis of the guaiane sesquiterpene (+)-orientalol F, Peter Metz of the Technische Universität Dresden needed (Eur. J. Org. Chem. 2016, 5881. DOI: 10.1002/ejoc.201601197) to epoxidize 30 to 32. He found that the dialkyl dioxirane prepared catalytically from 31, following Shi, was nicely selective.