C-N Ring Construction: The Synthesis of Decursivine by Mascal and by Jia

Abstract

Barry M. Trost and Justin Du Bois of Stanford University described (Org. Lett. 2011, 13, 3336) the cyclization of 1 to the activated aziridine 2. Liming Zhang of the University of California, Santa Barbara, rearranged (Angew. Chem. Int. Ed. 2011, 50, 3236) the propergylic amine 3 to the azetidinone 4 by N-H insertion of an intermediate Au carbene. Xiao Zheng and Pei-Qiang Huang of Xiamen University effected (J. Org. Chem. 2011, 76, 4952) reductive coupling of 6 with 7 to deliver the ester 8 . Eiji Tayama of Niigata University found (Tetrahedron Lett. 2011, 52, 1819) that 9 could be alkenylated with 10 with substantial retention of absolute configuration. Duncan J. Wardrop of the University of Illinois at Chicago, en route to a synthesis of (-)-swainsonine, observed (Org. Lett. 2011 , 13, 2376) high diastereocontrol in the cyclization of 12 to 13. Iain Coldham of the University of Sheffield also observed (J. Org. Chem. 2011, 76, 2360) substantial diastereoselection in the cyclization of 14 to 15. Robert E. Gawley of the University of Arkansas established (Org. Lett. 2011, 13, 394) that exposure of metalated 16 to just 5 mol % of a chiral ligand was sufficient to enable enantioselective coupling, to deliver 17. Christian Nadeau of Merck Frosst effected (J. Am. Chem. Soc. 2011, 133, 2878) enantioselective addition to the pyridinium salt 19 to give 20. Jiyong Hong of Duke University observed (Org. Lett. 2011, 13, 796) that enantiomerically pure 21 cyclized to the cis diastereomer of 22. With the Hayashi catalyst, cyclization could be driven toward the trans diastereomer, 22, enabling the synthesis of (+)-myrtine. Dawei Ma of the Shanghai Institute of Organic Chemistry found (Org. Lett. 2011, 13, 1602) that the Hayashi catalyst also directed the relative and absolute outcome in the addition of 24 to 23 , to give the piperidine 25. Donn G. Wishka of Pfizer/Groton devised (J. Org. Chem. 2011, 76, 1937) a practical route to the cis-substituted azepane 27, by Beckmann rearrangement of the enantiomerically pure 26 followed by reduction and oxidative cleavage.