C-N Ring Construction: The Waser Synthesis of Jerantinine E
James A. Bull of Imperial College London prepared (J. Org. Chem. 2013, 78, 6632. DOI: 10.1021/jo400956x) the aziridine 2 with high diastereocontrol by adding the anion of diiodomethane to the imine 1. Karl Anker Jørgensen of Aarhus University observed (Chem. Commun. 2013, 49, 6382. DOI: 10.1039/C3CC43506G) high ee in the distal aziridination of 3 to give 4. Benito Alcaide of the Universidad Complutense de Madrid and and Perdro Almendros of IQOG-CSIC Madrid reduced (Adv. Synth. Catal. 2013, 355, 2089. DOI: 10.1002/adsc.201300320) the β-lactam 5 to the azetidine 6. Hiroaki Sasai of Osaka University added (Org. Lett. 2013, 15, 4142. DOI: 10.1021/ol401817q) the allenoate 8 to the imine 7, delivering the azetidine 9 in high ee.
Tamio Hayashi of Kyoto University, the National University of Singapore, and A*STAR devised (J. Am. Chem. Soc. 2013, 135, 10990. DOI: 10.1021/ja406169s) a Pd catalyst for the enantioselective addition of the areneboronic acid 11 to the pyrroline 10. Ryan A. Brawn of Pfizer (Org. Lett. 2013, 15, 3424. DOI: 10.1021/ol401477r) reported related results. Nicolai Cramer of the Ecole Polytechnique Fédérale de Lausanne developed (J. Am. Chem. Soc. 2013, 135, 11772. DOI: 10.1021/ja406730t) a Ni catalyst for the cyclization of the formamide 13 to the lactam 14. Andrew D. Smith of the University of St. Andrews used (Org. Lett. 2013, 15, 3472. DOI: 10.1021/ol401554y) an organocatalyst to cyclize 15 to 16. Jose L. Vicario of the Universidad del Pais Vasco effected (Synthesis 2013, 45, 2669. DOI: 10.1055/s-0033-1338922) the multicomponent coupling of 17, 18, and 19, mediated by an organocatalyst, to construct 20 in high ee.
André Beauchemin of the University of Ottawa explored (J. Org. Chem. 2013, 78, 12735. DOI: 10.1021/jo4023149) the thermal cyclization of ω-alkenyl hydroxyl amines such as 21. Abigail G. Doyle of Princeton University developed (Angew. Chem. Int. Ed. 2013, 52, 9153. DOI: 10.1002/anie.201303994) a Ni catalyst for the enantioselective addition of aryl zinc bromides such as 24 to the prochiral 23, to give 25 in high ee. Dennis G. Hall of the University of Alberta developed (Angew. Chem. Int. Ed. 2013, 52, 8069. DOI: 10.1002/anie.201303931) an in situ preparation of the allyl boronate 26 in high ee. Addition to the aldehyde 27 proceeded with high diasteroselectivity. Slawomir Jarosz of the Polish Academy of Science prepared (Org. Lett. 2013, 15, 6214. DOI: 10.1021/ol403063v) the piperidine 31 by the addition of allyl magnesium bromide to the nitrile 29 followed by reduction with NaBH4.
Jérôme Waser, also of the Ecole Polytechnique Fédérale de Lausanne, rearranged (Angew. Chem. Int. Ed. 2013, 52, 13373. DOI: 10.1002/anie.201305533) the cyclopropane 32 with Cu triflate to give the ketone 33. This was carried on over several steps to Jerantinine E (34).