Enantioselective Synthesis of Alcohols and Amines: The Kim Synthesis of (+)-Frontalin
Vlada B. Urlacher of the Heinrich-Heine University Düsseldorf showed (Chem. Commun. 2014, 50, 4089. DOI: 10.1039/C4CC00647J) that the P450 monooxygenase CYP154A8 from Nocardia farcinica could monohydroxylate n-octane 1 to 2 with high regioselectivity and ee. Fener Chen of Fudan University used (J. Org. Chem. 2014, 79, 2723. DOI: 10.1021/jo402829b) an organocatalyst to open the prochiral anhydride 3 to the monoester 4. Amir H. Hoveyda of Boston College added (Angew. Chem. Int. Ed. 2014, 53, 3387. DOI: 10.1002/anie.201309982) bis(pinacolato)diboron to the enone 5 to give 6, that was readily oxidized to the tertiary alcohol.
Matthias Breuning of the University of Bayreuth designed (Chem. Commun. 2014, 50, 6623. DOI: 10.1039/C4CC02429J) a Cu catalyst for the enantioselective Henry addition of nitromethane to the aldehyde 7 to give 8. Benjamin List of the Max-Planck-Institute Mülheim optimized (Synlett 2014, 25, 932. DOI: 10.1055/s-0033-1340919) the proline-catalyzed formation of the aldol product 10 from the aldehyde 9. Christian Wolf of Georgetown University devised (Chem. Commun. 2014, 50, 3151. DOI: 10.1039/C4CC00394B) the alkyne 12, that could be added to the aldehyde 11 to give 13 in high ee.
Keiji Maruoka of Kyoto University developed (Org. Lett. 2014, 16, 1530. DOI: 10.1021/ol5000742) practical conditions for the organocatalyzed addition of an aldehyde 14 to an in situ-generated nitroso urethane, leading, after reduction, to the alcohol 15. Satoko Kezuka of Tokai University added (Tetrahedron Lett. 2014, 55, 2818. DOI: 10.1021/ol5000742) the benzyloxyamine 17 to the nitro alkene 16 to give the coupled product 18 in high ee. Xiaohua Liu and Xiaomiong Feng of Sichuan University developed (Angew. Chem. Int. Ed. 2014, 53, 1636. DOI: 10.1002/anie.201308501) a Pd catalyst for the preparation of 20 by the enantioselective amination of the diazo ester 19. Shou-Fei Zhu and Qi-Lin Zhou of Nankai University described (Angew. Chem. Int. Ed. 2014, 53, 2978. DOI: 10.1002/anie.201309820) related work, not illustrated, on the enantioselective aryloxylation of an α-diazo ester. Alan Armstrong of Imperial College London, taking advantage (J. Org. Chem. 2014, 79, 3895. DOI: 10.1021/jo500341e) of the ready availability of enantiomerically secondary selenides such as 21, showed that it could be converted to the corresponding α-chiral amine 23.
Claudio Palomo of the Universidad Pais Vasco devised (Chem. Eur. J. 2014, 20, 6526. DOI: 10.1002/chem.201304877) an organocatalyst for the enantioselective addition of 25 to the imine 24. The product was readily desufonylated to 26. Gilles Dujardin of the Université du Maine and Sandrine Py of the Université Joseph Fourier showed (Org. Lett. 2014, 16, 1936. DOI: 10.1021/ol500483t) that the dipolar cycloaddition of 27 to the vinyl ether 28 proceeded with high diastereocontrol. The three alkyl branches of the product 29 were readily differentiated one from another.
Frontalin (33) is an insect pheremone that has also been detected in elephants. Hee-Doo Kim of Sookmyung Women’s University prepared 33 (Synlett 2014, 25, 251. DOI: 10.1055/s-0033-1340163) by the highly diastereocontrolled 1,2-addition of 31 to the ketone 30.