Organic Chemistry Portal
Organic Chemistry Highlights

Monday, March 20, 2017
Douglass F. Taber
University of Delaware

Reduction of Organic Functional Groups

David F. Wiemer of the University of Iowa showed (Tetrahedron Lett. 2016, 57, 1335. DOI: 10.1016/j.tetlet.2016.02.041) that deoxygenation of the epoxide 1 proceeded with retention of alkene geometry. Yoshiaki Nakao of Kyoto University devised (Chem. Lett. 2016, 45, 45. DOI: 10.1246/cl.150807) the deoxygenation of 3 to 4. Methyl ethers were stable.

Jakob Magolan of the University of Idaho developed (Tetrahedron 2016, 72, 3748. DOI: 10.1016/j.tet.2016.03.017) an alternative to the Luche reduction of 5 to 6, using alumina. Rylan J. Lundgren of the University of Alberta established (Chem. Commun. 2016, 52, 958. DOI: 10.1039/C5CC07993D) complementary conditions, using respectively Ir or Rh, to effect allylic deoxygenation, as exemplified by the conversion of 7 to 9 using 8. Murphy V. R. K. Motoru of Laurus Laboratories found (Org. Process Res. Dev. 2016, 20, 609. DOI: 10.1021/acs.oprd.5b00286) that even the unreactive mesylate 10 could be reduced to 11. Chao-Jun Li of McGill University employed (J. Am. Chem. Soc. 2016, 138, 5433. DOI: 10.1021/jacs.6b02344) a borrowed hydrogen approach to effect deoxygenation of 12 to 13.

Laurel L. Schafer of the University of British Columbia combined (Adv. Synth. Catal. 2016, 358, 713. DOI: 10.1002/adsc.201500861) the alkyne 14 with 15 to prepare the linear amine 16. In a complementary approach, Neeraj Kumar of CSIR-Institute of Himalayan Bioresource Technology aminated (Adv. Synth. Catal. 2016, 358, 1103. DOI: 10.1002/adsc.201501088) 17 with 18 to assemble the branched amine 19.

Kommu Nagiah of the Indian Institute of Chemical Technology took advantage (Adv. Synth. Catal. 2016, 358, 81. DOI: 10.1002/adsc.201500678) of the in situ generation of the diazoalkane from the tosylhydrazone of 20 (Stereocontrolled Carbocyclic Construction: (-)-Mintlactone (Bates), (-)-Gleenol (Kobayashi), (-)-Vibralactone C (Snider) 2009, August 9), combining it under Rh catalysis with 21 to assemble the protected primary amine 22. Viresh H. Rawal of the University of Chicago oxidized (Angew. Chem. Int. Ed. 2016, 55, 3077. DOI: 10.1002/anie.201510909) the trityl hydrazone of 23 with NBS to give the bromide 25.

Amides can be reduced to amines, aldehydes or alcohols. A protocol for the first transformation was reported (Chem. Eur. J. 2016, 22, 7050. DOI: 10.1002/chem.201600535) by Matthias Beller of the Universitšt Rostock. The reduction of 28 to the aldehyde 29 was described (Angew. Chem. Int. Ed. 2016, 55, 4562. DOI: 10.1002/anie.201600097) by Fredrik Tinnis and Hans Adolfsson of Stockholm University. Bakthan Singaram of the University of California, Santa Cruz developed (J. Org. Chem. 2016, 81, 3619. DOI: 10.1021/acs.joc.6b00276) Li pyrrolidinoborohydride for the reduction of 30 to 31.

In what is really an oxidation, Bin Xiao and Yao Fu of the University of Science and Technology of China effected (Chem. Commun. 2016, 52, 1242. DOI: 10.1039/C5CC08393A) the net reductive demethylation of 32. The amide 33 so produced was readily hydrolyzed to the carboxylic acid.

D. F. Taber, Org. Chem. Highlights 2017, March 20.