Organic Chemistry Portal
Organic Chemistry Highlights

Monday, May 28, 2018
Douglass F. Taber
University of Delaware

Organic Functional Group Conversion: The Gleason Synthesis of Virosaine A

Hai-Zhu Yu of Anhui University and Chaozhong Li of the Shanghai Institute of Organic Chemistry selectively exchanged (Angew. Chem. Int. Ed. 2017, 56, 15411. DOI: 10.1002/anie.201708197) the tertiary iodide of 1, leading to 2. Radhey M. Singh of Banaras Hindu University developed (Org. Biomol. Chem. 2017, 15, 9979. DOI: 10.1039/C7OB02431B) mild conditions for converting the dibromo alkene 3 to the alkyne 4. Gerald B. Hanmond of the University of Louisville and Bo Xu of Donghua University devised (Org. Lett. 2017, 19, 4524, DOI: 10.1021/acs.orglett.7b02101; ACS Catal. 2017, 7, 6798, DOI: 10.1021/acscatal.7b02567) a gold catalyst for the hydrochlorination of the alkyne 5 to give 6. Daniel P. Furkert and Margaret A. Brimble of the University of Auckland established (Org. Lett. 2017, 19, 5418. DOI: 10.1021/acs.orglett.7b02687) a protocol for the regioselective hydration of the propargylic alcohol 7 to the α-hydroxy ketone 8.

Shao-Hua Wang of Lanzhou University and Yong-Qiang Tu of Shanghai Jiao Tong University showed (Org. Lett. 2017, 19, 4648. DOI: 10.1021/acs.orglett.7b02274) that the sulfoxide from a simple phenyl alkyl ether 9 could be eliminated to form the terminal alkene 10. Gang Xu and Liyan Dai of Zhejiang University devised (Tetrahedron 2017, 73, 5321. DOI: 10.1016/j.tet.2017.07.033) the readily recyclable reagent 13 for Mitsunobu coupling, including the union of 11 with 12 to give 14.

Maurice Brookhart and Olafs Daugulis of the University of Houston used (Chem. Commun. 2017, 53, 10010. DOI: 10.1039/C7CC04953F) an air-stable Pd catalyst to isomerize the silyl ether 15 to the enol ether 16. Nicola L. B. Pohl of Indiana University showed (Org. Lett. 2017, 19, 4516. DOI: 10.1021/acs.orglett.7b02080) that a combination of the Bi reagent 18 and propanethiol 19 mediated the rapid coupling of 17 with 20 to give 21.

John E. Moses of La Trobe University used (Chem. Eur. J. 2017, 23, 9990. DOI: 10.1002/chem.201701552) 23 to convert 22 into the acid fluoride, that was then coupled with 24 to give 25. Kazushi Mashima of Osaka University activated (Eur. J. Org. Chem. 2017, 5010. DOI: 10.1002/ejoc.201700748) the secondary amide 26 by alkylation with the epoxide 27, then exchanged that product with 28 to give the ester 29. Corinne Gosmini and Grégory Danoun of the Ecole Polytechnique reported (Chem. Eur. J. 2017, 23, 10043. DOI: 10.1002/chem.201702608 ) related results. Duen-Ren Hou of the National Central University assembled (J. Org. Chem. 2017, 82, 10201. DOI: 10.1021/acs.joc.7b01705) the thioester 33 by activating the carboxylic acid 30 with 31, then alkyating that product with 32. Paramjit S. Arora of New York University designed (Org. Lett. 2017, 19, 5122. DOI: 10.1021/acs.orglett.7b02412) an organocatalyst for the coupling of the peptide 34 with the thioester 35.

Virosaine A (39), isolated from the Chinese waterberry Flueggea virosa, has a challenging pentacyclic structure. En route to 39, James L. Gleason of McGill University metalated (Angew. Chem. Int. Ed. 2017, 56, 10830, DOI: 10.1002/anie.201706273; Tetrahedron 2018, 74, 759, DOI: 10.1016/j.tet.2017.12.026) 37, then brominated the alkyl lithium so formed, leading to 38.

D. F. Taber, Org. Chem. Highlights 2018, May 28.