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Monday, July 15, 2019
Douglass F. Taber
University of Delaware

Alkylated Stereogenic Centers: The Hong Synthesis of (-)-Melinonine E

Xiu-Qin Dong and Xumu Zhang of Wuhan University reported that the lactam 1 could be hydrogenated to 2 in high ee (Org. Biomol. Chem. 2018, 16, 8819. DOI: 10.1039/C8OB02231C). Stephen L. Buchwald of MIT effected hydroamination of 3 with 4 to give 5 in high de (J. Am. Chem. Soc. 2018, 140, 15976. DOI: 10.1021/jacs.8b10564). Yu-Fei Ao of the Institute of Chemistry, Chinese Academy of Sciences, after selectively hydrolyzed the prochiral bis amide 6, then isolated the product as the benzyl ester 7 (Adv. Synth. Catal. 2018, 360, 4594. DOI: 10.1002/adsc.201800956). Kami L. Hull, now at the University of Texas, devised the 1,3-H atom migration and subsequent oxidative coupling with 9 that transformed 8 into the ester 10 (Chem. Commun. 2018, 54, 7814. DOI: 10.1039/C8CC02612B).

Kuiling Ding of the Shanghai Institute of Organic Chemistry added the aldehyde 12 to the alkene 11, leading to the ketone 13 (J. Am. Chem. Soc. 2018, 140, 10374. DOI: 10.1021/jacs.8b07125). Ryan J. Lundgren of the University of Alberta constructed 16 by allylic coupling of 15 with 14 (J. Am. Chem. Soc. 2018, 140, 17418. DOI: 10.1021/jacs.8b11390). Haibo Mei and Jianlin Han of Nanjing University added both the N-alkoxy phthalimide 18 and TMS-CN to the alkene 17 to give 19 (ACS Catal. 2018, 8, 7489. DOI: 10.1021/acscatal.8b01863). Huw M. L. Davies of Emory University and Christopher W. Jones of Georgia Tech described an immobilized Rh catalyst that could be used in flow to mediate the insertion of 20 into MTBE 21 to give 22 (Angew. Chem. Int. Ed. 2018, 57, 10923. DOI: 10.1002/anie.201805528).

Kensuke Kiyokawa and Satoshi Minakata of Osaka University and Masahiro Yamanaka of Rikkyo University effected enantioselective cyanation of 23, leading to 24 (Chem. Eur. J. 2018, 24, 17027. DOI: 10.1002/chem.201804455). Clark R. Landis and Jennifer M. Schomaker of the University of Wisconsin developed conditions for the hydroformylation of 25 to 26 (J. Org. Chem. 2018, 83, 10207. DOI: 10.1021/acs.joc.8b01431). Gregory C. Fu of Caltech added the racemic β-lactam 28 to 1-hexene (27), leading to 29 (Nature 2018, 563, 379. DOI: 10.1038/s41586-018-0669-y). Shaozhong Ge of the National University of Singapore cyclized 30 to 31 in high ee (J. Am. Chem. Soc. 2018, 140, 10687. DOI: 10.1021/jacs.8b06814).

Melinonine E (35) was isolated from the Amazonian liana Strychnos melinoniana baillon. To prepare the starting material 34 for a synthesis of 35, Ran Hong of the Shanghai Institute of Organic Chemistry used the Boeckman protocol to add formaldehyde to the aldehyde 32, then condensed the product with the phosphonate 33 (Tetrahedron 2018, 74, 5791. DOI: 10.1016/j.tet.2018.08.015).

D. F. Taber, Org. Chem. Highlights 2019, July 15.