Functional Group Interconversion: The Wang Synthesis of Merrilactone A
Sarah E. Reisman of Caltech showed that the cesium salt 1 of a half oxalate could be converted to the corresponding chloride 3 by irradiation in the presence of 2 (Org. Lett. 2018, 20, 4912. ). Declan G. Gilheany of University College Dublin found that chlorination of triphenylphosphine oxide (4) with oxalyl chloride (5) gave an intermediate that reacted with the Grignard reagent 6 to give the phosphonium salt 7 (Chem. Commun. 2018, 54, 5843. ). Nobukazu Taniguchi of Fukushima Medical University prepared the thioacetal 10 by the addition of the thiophenol 9 to the alkyne 8 (Synlett 2018, 29, 2712. ). Johannes F. Teichert of the Technische Universität Berlin observed high geometric and regiocontrol in the hydrobromination of 11 with 12, leading to the bromoalkene 13 (Org. Lett. 2018, 20, 4926. ). David E. Bergbreiter of Texas A&M University demonstrated the advantages of liquid medium molecular weight (300~500) alkanes for the handling of pyrophoric alkyl lithium reagents (Tetrahedron Lett. 2018, 59, 3926. ).
László Kürti of Rice University devised the reagent 15 for the conversion of a Grignard reagent 14 directly to the primary amine 16 (Org. Lett. 2018, 20, 8064. ). Jia-heng Zhang of the Harbin Institute of Technology and Xian-Jin Yang of the East China University of Science and Technology used the reagent 18 to convert the alcohol 17 to the sulfonamide 19 (Eur. J. Org. Chem. 2018, 3920. ). Baolin Yin of the South China University of Technology assembled the ether 23 by coupling tetrahydrofuran (20) with the diazo ester 21 in the presence of the sulfonamide 22 (J. Org. Chem. 2018, 83, 14385. ). Keary M. Engle of Scripps/La Jolla used the 8-aminoquinoline (AQ) group to direct the activation of the ether of 24, leading to coupling with 25 to give 26 ( Nature Chem. 2018, 10, 1126. ).
Mitchell P. Croatt of the University of North Carolina at Greensboro devised a surprisingly mild reagent combination for the conversion of a primary amide 27 to the nitrile 28 (Org. Lett. 2018, 20, 6046. ). Gregory L. Beutner of Bristol-Myers Squibb used 30 to promote the activation of 29 with N-methylimidazole, allowing coupling with 31 to give 32 (Org. Lett. 2018, 20, 4218. ). Huangdi Feng of the Shanghai Institute of Organic Chemistry and Xiaohui Liu of the Shanghai University of Engineering Science reported an alternative activation (not illustrated), the addition of the carboxylic acid to methyl propiolate (J. Org. Chem. 2018, 83, 7962. ). R. M. Koenigs of RWTH Aachen University and T. V. Nguyen of the University of New South Wales showed that tropyllium ion (34) could catalyze the opening of the β-diketone 33 with 35 to give 36 (Chem. Commun. 2018, 54, 12970. ). Kounosuke Oisaki and Motomu Kanai of the University of Tokyo devised a mild protocol for the conversion of a C-terminal peptide 37 to the corresponding thioacid 38 (Chem. Commun. 2018, 54, 12222. ).
Merrilactone A (41) shows promising activity in cortical neuron cell culture. En route to 41, Bo Wang of the Changchun Institute of Applied Chemistry converted the ketone 39 to the alkyne 40 (Chem. Eur. J. 2018, 24, 16511. ).