Reduction: The Beller Synthesis of Peronatin B
Antonio M. Echavarren of ICIQ demonstrated (Angew. Chem. Int. Ed. 2017, 56, 14591. ) the selective hydrogenation of 1 to 2. Kiyotake Suenaga of Keio University used (J. Org. Chem. 2017, 82, 12503. ) diimide to reduce 3 to 4, sparing the benzyl ethers.
Masahito Murai and Kazuhiko Takai of Okayama University developed (Chem. Commun. 2017, 53, 9281. ) a mild procedure for the selective reductive cleavage of unactivated cyclopropanes, converting 5 to 6. Robert Madsen of the Technical University of Denmark devised (Eur. J. Org. Chem. 2017, 5417. ) a protocol for the conversion of an alcohol 7 to the alkane 8, with the loss of one carbon. Frederic Beisson of Aix-Marseille University used (Science 2017, 357, 903. ) a light-driven enzyme to reduce the medium chain acid 9 to the alkane 10, also with the loss of one carbon. F. Dean Toste of the University of California, Berkeley effected (J. Am. Chem. Soc. 2017, 139, 14001. ) the selective reduction of 11 to the diacid 12.
Jose C. Gonzalez-Gomez of the Universidad de Alicante removed (Adv. Synth. Catal. 2018, 359, 2857. ) the amino group of 13, leading to 14. Xuechen Li of the University of Hong Kong accomplished (Angew. Chem. Int. Ed. 2017, 56, 14607. ) the desulfurative deuteration of 16, leading to 17. Hai Dong of the Huazhong University of Science and Technology reported (J. Org. Chem. 2017, 82, 7008. ) a related desulfurization. Bill Morandi of the Max-Planck-Institut für Kohlenforschung showed (Synlett 2017, 28, 2425. ) that the silane 22 was an effective reagent for coupling the alcohol 21 with the ketone 20 to give the ether 23. Daniel Seidel of Rutgers University described (J. Am. Chem. Soc. 2017, 139, 10224. ) related results. Julie A. Pigza of the University of Southern Mississippi established (Tetrahedron Lett. 2017, 58, 3024. ) a two-step procedure for reducing an ester 24 to the ether 25. Note that the first step is also a general method for reducing an ester to the corresponding protected aldehyde. Denis Chusov of the A. N. Nesmeyanov Institute of Organoelement Compounds carried out (Org. Biomol. Chem. 2017, 15, 10164. ) reductive amination of 26 with the amine 27 using the inexpensive and non-toxic Fe(CO)5.
Thomas Schaub of BASF accomplished (ChemCatChem 2017, 9, 4175. ) the direct reduction of the nitrile 29 to the alcohol 30. These are much milder conditions than those previously described (Tetrahedron Lett. 2001, 42, 8007).
In the course of a synthesis of peronatin B (33), Matthias Beller of the Universität Rostock used (Angew. Chem. Int. Ed. 2017, 56, 11242. ) a Br substituent to direct the regioselectivity of indole formation, leading to 31. He then used a biomass-derived Co catalyst to reduce 31 to the desired 32.