Enantioselective Synthesis of Alcohols and Amines: The Huang Synthesis of Rosiridol
Martin Wills of the University of Warwick observed that the α-sulfonyl ketone 1 could be reduced with high enantioselectivity to the alcohol 2 (Angew. Chem. Int. Ed. 2020, 59, 14265. DOI: 10.1002/anie.202004658). Masaya Sawamura of Hokkaido University showed that γ-borylation of the ester 3 could be followed up with oxidation, leading to the alcohol 4 (Science 2020, 369, 970. DOI: 10.1126/science.abc8320).
Aleksandr E. Rubtsov of Perm State University and Andrei V. Malkov of the University of Loughborough used a bipyridine N,N'-dioxide to direct the addition of trichlorosilylallene 6 to the aldehyde 5, to give the propargylated product 7 (Adv. Synth. Catal. 2020, 362, 5467. DOI: 10.1002/adsc.202000936). Chao Wang of Shaanxi Normal University used a borrowed hydrogen strategy (Guerbet reaction) to assemble the secondary alcohol 10 by the coupling of the alcohol 8 with the primary alcohol 9 (Angew. Chem. Int. Ed. 2020, 59, 11408. DOI: 10.1002/anie.202003104). Declan G. Gilheany of University College Dublin used a stoichiometric amount of an easily-recoverable amino alcohol to mediate the addition of the Grignard reagent 12 to the ketone 11, leading to the tertiary alcohol gossonorol (13) (Org. Lett. 2020, 22, 8198. DOI: 10.1021/acs.orglett.0c02629). Nicolai Cramer of the Ecole Polytechnique Fédérale de Lausanne constructed the butenolide 16 by the oxidative coupling of the unsaturated acid 15 with the allene 14 (ACS Catal. 2020, 10, 8231. DOI: 10.1021/acscatal.0c02430).
Mu-Hyun Baik of KAIST and Simon B. Blakey of Emory University effected allylic amination of the alkene 17 with 18, leading to the allylic amide 19 (J. Am. Chem. Soc. 2020, 142, 13996. DOI: 10.1021/jacs.0c07305). Pingfan Li of the Beijing University of Chemical Technology and Jianwei Sun of the Hong Kong University of Science and Technology used a chiral phosphoric acid to mediate the coupling of the aniline 21 with the α-keto sulfur ylide 20, leading to the α-amino ketone 22 (J. Am. Chem. Soc. 2020, 142, 14384. DOI: 10.1021/jacs.0c07210).
Haohua Huo of Xiamen University activated the acid 23 in situ with dimethyl dicarbonate, then used an Ir photocatalyst and visible light to assemble the amine 25 by coupling the intermediate anhydride with the amine 24 (J. Am. Chem. Soc. 2020, 142, 19058. DOI: 10.1021/jacs.0c10471). Chuan-Ming Yu and Bin Mao of the Zhejiang University of Technology assembled the propargyl amine 28 by the conjugate addition of the alkynyl trifluoroborate 27 to the enone 26 (Org. Lett. 2020, 22, 7427. DOI: 10.1021/acs.orglett.0c02394). Professor Cramer combined conjugate addition with amine transfer to prepared 31 by the coupling of the enol ether 29 with the acrylate 30 (Angew. Chem. Int. Ed. 2020, 59, 14129. DOI: 10.1002/anie.202006149). Chang Guo of the University of Science and Technology of China combined Ni catalysis with Cu catalysis to prepare 34 by the enantioselective alkylation of the imine 32 with the propargylic carbonate 33 (Angew. Chem. Int. Ed. 2020, 59, 14270. DOI: 10.1002/anie.202005019).
Yi-Yong Huang of the Wuhan University of Technology used a chiral phosphoric acid to mediate the enantioselective addition of the allylic boronate 36 to the aldehyde 35. Exposure of 37 to triflic acid delivered rosiridol (38) (Chem. Commun. 2020, 56, 10030. DOI: 10.1039/D0CC00367K).