Organic Chemistry Portal
Organic Chemistry Highlights

Monday, September 21, 2015
Douglass F. Taber
University of Delaware

Reactions of Alkenes: The Usami Synthesis of (-)-Pericosine E

Dasheng Leow of the National Tsing Hua University used (Eur. J. Org. Chem. 2014, 7347. DOI: 10.1002/ejoc.201403021) photolysis to activate the air oxidation of hydrazine to generate diimide, that then reduced 1 selectively to 2. Kevin M. Peese of Bristol-Myers Squibb effected (Org. Lett. 2014, 16, 4444. DOI: 10.1021/ol5019739) ring-closing metathesis of 3 followed by in situ reduction to form 4.

Jitendra K. Bera of the Indian Institute of Technology Kanpur effected (J. Am. Chem. Soc. 2014, 136, 13987. DOI: 10.1021/ja5075294) gentle oxidative cleavage of cyclooctene 5 to the dialdehyde 6. Arumugam Sudalai of the National Chemical Laboratory observed (Org. Lett. 2014, 16, 5674. DOI: 10.1021/ol5027393) high regioselectivity in the oxidation of the alkene 7 to the ketone 8.

Hao Xu of Georgia State University also observed (J. Am. Chem. Soc. 2014, 136, 13186. DOI: 10.1021/ja506532h) high regioselectivity in the oxidation of the alkene 9 to the cyclic urethane 11. Justin Du Bois of Stanford University developed (J. Am. Chem. Soc. 2014, 136, 13506. DOI: 10.1021/ja508057u) mild conditions for the net double amination of the alkene 12, leading to 14.

Jiaxi Xu and Pingfan Li of the Beijing University of Chemical Technology devised (Org. Lett. 2014, 16, 6036. DOI: 10.1021/ol5031348) a protocol for the allylic thiomethylation of an alkene, converting 15 to 17. Matthias Beller of the Leibniz-Institut für Katalyse combined (Chem. Eur. J. 2014, 20, 15692. DOI: 10.1002/chem.201404294) hydroformylation, aldol condensation and reduction to convert the alkene 18 to the ketone 19.

Phil S. Baran of Scripps/La Jolla added (Angew. Chem. Int. Ed. 2014, 53, 14382. DOI: 10.1002/anie.201408022) the diazo dienone 21 to the alkene 20 to give, after exposure to HCl, the arylated product 22. Markus R. Heinrich of the Friedrich-Alexander-Universität Erlangen-Nürnberg employed (Chem. Eur. J. 2014, 20, 15344. DOI: 10.1002/chem.201405229) Selectfluor as both an oxidizing and a fluorinating agent in the related conversion of 23 to 25. Debabrata Maiti the Indian Institute of Technology Bombay activated (J. Am. Chem. Soc. 2014, 136, 13602. DOI: 10.1021/ja5082734) the ortho position of 27, then added that intermediate to 26 to give 28. John F. Bower of the University of Bristol used (J. Am. Chem. Soc. 2014, 136, 10258. DOI: 10.1021/ja505776m) an Ir catalyst to achieve the opposite regioselectivity in the addition of 30 to 29 to give 31.

Although originally isolated from the sea hare Aplysia kurodai, (-)-Pericosine E (35) was later shown to in fact be produced by the fungus Periconia byssoides. In the course of a synthesis of 35, Yoshihide Usami of the Osaka University of Pharmaceutical Sciences found (Org. Lett. 2014, 16, 3760. DOI: 10.1021/ol501631r) that trifluoromethyl methyl dioxirane (TFDO) epoxidized 32 to 34 with high selectivity.

D. F. Taber, Org. Chem. Highlights 2015, September 21.