Stereocontrolled Carbocyclic Construction The Mulzer Synthesis of - -Penifulvin

Tanmaya Pathak of the Indian Institute of Technology, Kharagpur devised (J. Org. Chem. 2009, 74y 2710) a preparation of enantiomerically-pure oxygenated cyclopropanes such as 3 from carbohydrate precursors. Andrei K. Yudin of the University of Toronto established (Organic Lett. 2009,11, 1281) a route to aminated cyclobutanes such as 5 based on sigma-tropic rearrangement of the P-Iactam 4. 

Stephen C. Bergmeier of Ohio University reported (refraAerfron 2009, 65, 74I)asmdy of the balance between five- and six-membered ring formation in the cyclization of aziri- 

Ullrich Jahn of the Academy of Sciences of the Czech Republic observed (Chem. Eur. J. 2009,15, 58) that the free-radical cyclization of 11 proceeded to give mainly the diaste-reomer 12 ( 1 1 at the secondary allylic position). Daesung Lee of the University of Illinois at Chicago reasoned (J. Am. Chem. Soc. 2009, 131, 8413) that the stereochemical relationship between the O and the adjacent C-H of 13 was such that the C-H would be deactivated. The cyclization of the alkylidene carbene derived from 13 indeed proceeded to give 14, setting the stage for the synthesis of platensimycin. 

Marco A. Cufolini of the University of British Columbia found (Organic Lett. 2009,11, 1539) an easy protocol for the generation of a nitrile oxide and subsequent dipolar cycloaddition, by oxidation of the oxime. In a related investigation, Adam J. M. Burrell and 

Iain Coldham of the University of Sheffield cychzed Organic Lett. 2009, 11, 1515) the oxime derived from 18, by way of the intermediate nitrone, to give 19 with high diastereocontrol. 

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