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Monday, June 29, 2015
Douglass F. Taber
University of Delaware

C-C Bond Construction: The Hou Synthesis of (-)-Brevipolide H

Yao Fu and Lei Liu of the University of Science and Technology of China devised (Chem. Eur. J. 2014, 20, 15334. ) conditions for the coupling of a halide 2 with a tosylate 1 with inversion of absolute configuration. Hegui Gong of Shanghai University coupled (J. Am. Chem. Soc. 2014, 136, 17645. ) the glucosyl bromide 4 with an anhydride 5 to give the ketone 6.

Luigi Vaccaro of the Universitŕ di Perugia showed (Org. Lett. 2014, 16, 5721. ) that tetrabutylammonium fluoride (TBAF) promoted the opening of the epoxide 7 with the ketene silyl acetal 8, leading to the lactone 9. Valérie Desvergnes and Yannick Landais of the University of Bordeaux assembled (Chem. Eur. J. 2014, 20, 9336. ) the diketone 12 by using a Stetter catalyst to promote the conjugate addition of the acyl silane 11 to the enone 10.

Thomas Werner of the Leibniz-Institute for Catalysis reported (Eur. J. Org. Chem. 2014, 6873. ) the enantioselective conversion of the prochiral triketone 13 to the bicyclic enone 15 by an intramolecular Wittig reaction. Elizabeth H. Krenske of the University of Queensland and Christopher J. O'Brien also reported (Angew. Chem. Int. Ed. 2014, 53, 12907. ) progress (not illustrated) on catalytic Wittig reactions.

Michael J. Krische of the University of Texas showed (J. Am. Chem. Soc. 2014, 136, 11902. ) that Ru-mediated addition of 17 to the aldehyde derived in situ from 16 gave 18 with high Z-selectivity. Vladimir Gevorgyan of the University of Illinois at Chicago constructed (J. Am. Chem. Soc. 2014, 136, 17926. ) the trisubstituted alkene 20 by the intramolecular Heck cyclization of 19. Kálmán J. Szabó of Stockholm University optimized (Chem. Commun. 2014, 50, 9207. ) the Pd-catalyzed borylation of the alkene 21 followed by in situ addition to the aldehyde 22 to give 23.

Boris A. Trofimov of the Irkutsk Institute of Chemistry Siberian Branch developed (Eur. J. Org. Chem. 2014, 4463. ) aqueous conditions for the preparation of a propargylic alcohol 26 by the addition of an alkyne 25 to the ketone 24. Huanfeng Jiang of the South China University of Technology prepared (Angew. Chem. Int. Ed. 2014, 53, 14485. ) the alkyne 28 by the oxidative elimination of the tosylhydrazone 27. Matthias Brewer of the University of Vermont fragmented (J. Org. Chem. 2014, 79, 6037. ) the ketone 29 to the keto alkyne 31 by the addition of ethyl diazoacetate 30 followed by exposure of the adduct to SnCl4. Mariappan Periasamy of the University of Hyderabad prepared (Eur. J. Org. Chem. 2014, 6067. ) a propargylic amine by combining 32, 33 and 34, then eliminated it to the enantiomerically pure allene 35 by warming with ZnBr2.

The breviolides, isolated from Hyptis brevipes and Lippia alva, are inhibitors of the chemokine receptor CCR5. Preparing the starting material for a synthesis of ent-Brevipolide 39, Duen-Ren Hou of National Central University took advantage (Org. Lett. 2014, 16, 5328. ) of the superior reactivity of allylic alcohols in Ru-mediated cross metathesis, combining 36 with 37 to make 38.

D. F. Taber, Org. Chem. Highlights 2015, June 29.
URL: https://www.organic-chemistry.org/Highlights/2015/29June.shtm