Functional Group Interconversion: The Minehan Synthesis of Jambolanin C
Julian G. West of Rice University used a vitamin B12-based catalyst to prepare the terminal alkene 2 by the elimination of the primary bromide 1 (Chem. Sci. 2021, 12, 1736. ). Jung-Woo Park of KAIST assembled the allyl silane 5 by coupling the internal alkyne 3 with the trialkylsilane 4 (ACS Catal. 2021, 11, 1548. ).
Daniele Leonori of the University of Manchester effected the selective oxidative demethylation of the tertiary amine 6 to give the secondary amine 7 (Angew. Chem. Int. Ed. 2021, 60, 7669. ). Hélène Lebel of the Université de Montréal used a flow system with the dinitrite 9 to couple the acid 10 with the diazonium salt derived from the primary amine 8, leading to the ester 11 (Chem. Commun. 2020, 56, 10938. ). Jonathan Clayden of the University of Bristol showed that the Mitsunobu coupling of N-Boc ethyl oxamate 13 with the allylic alcohol 12 followed by hydrolysis led to the amine 14 with clean inversion of absolute configuration (J. Org. Chem. 2021, 86, 8538. ). Armido Studer of Westfalische Wilhelms-Universität devised the iron-catalyzed Markovnikov hydration of the terminal alkene 15 to the secondary alcohol 16 (Angew. Chem. Int. Ed. 2021, 60, 8313. ).
Andrey F. Asachenko of the A. V. Topchiev Institute of Petrochemical Synthesis optimized the selective hydration of the internal aryl alkyne 17 to the benzyl ketone 18 (Chem. Commun. 2021, 57, 5686. ). Qian Liao of the Dalian University of Technology and Nicolas Mézailles of the Université Paul Sabatier exposed a Mo complex to N2, then used that to split the internal alkyne 19 into the two nitriles 20 and 21 (Angew. Chem. Int. Ed. 2021, 60, 12242. ).
Maya Shankar Singh of Banaras Hindu University prepared the alkynyl sulfide 23 by the net elimination of H2S from the β-oxodithioester 22 (J. Org. Chem. 2021, 86, 5908. ). Hui-cheng Cheng and Jiao-li Ma of the Guangdong University of Petroleum Technology showed that arylation of the nitrile 24 led to the amide 25 (Tetrahedron Lett. 2021, 71, 153048. ). Haoran Sun of the University of South Dakota used 27 to convert the carboxylic acid 26 to the acid fluoride 28 (J. Org. Chem. 2021, 86, 6066. ). Akira Matsumoto and Keiji Maruoka of Kyoto University reported that Selectfluor can also be used to effect this transformation (J. Org. Chem. 2021, 86, 5401. ). Munetaka Kunishima of Kanazawa University developed the reagent 30 for preparing the ester 32 by coupling the acid 29 with the alcohol 31 (Org. Biomol. Chem. 2021, 19, 4712. ).
Thomas Gerard Minehan of California State University, Northridge showed that addition of the enolate from 33 to the nitroalkene 34 gave an intermediate that on acid hydrolysis was converted to the diketone 35. Intramolecular aldol condensation followed by desilylation then completed the synthesis of jambolanin C (36) (J. Org. Chem. 2021, 86, 3074. ).