New Methods for Carbocyclic Construction: The Kim Synthesis of Pentalenene
Daesung Lee of the University of Illinois, Chicago, taking advantage of the facile insertion of an alkylidene carbene into a C-Si bond, established (J. Am. Chem. Soc. 2010, 132, 6640) a general method for the conversion of an α-silyl ketone 1 into the silyl cyclopropene 3. Christopher D. Bray of Queen Mary University showed (J. Org. Chem. 2010, 75, 4652) that the sulfonyl phosphonate 5 converted the enantiomerically pure epoxide 4 into the cyclopropane 6. Paul Margaretha of the University of Hamburg observed (Organic Lett. 2010, 12, 728) smooth photochemical combination of 7 and 8 to give 9 with high diastereocontrol. Tõnis Kanger of the Tallinn University of Technology devised (Organic Lett. 2010, 12, 2230) the three-component coupling of 10, 11, and diethyl amine to give, after reduction, the highly substituted cyclobutane 12. Min Shi of the Shanghai Institute of Organic Chemistry uncovered (J. Org. Chem. 2010, 75, 902) an interesting new thermal rearrangement: the conversion of 13 to 14. José G. Ávila-Zárraga of the Universidad Nacional Autónoma de México applied (Tetrahedron Lett. 2010, 51, 2232) Pd catalysis to the cyclization of the epoxy nitrile 15, redirecting the reaction from the expected cyclobutane to the cyclopentanol 16. Ullrich Jahn of the Academy of Sciences of the Czech Republic effected (J. Org. Chem. 2010, 75, 4480) the oxidative radical cyclization of 17 to 18. Initial deprotonation of the substrate with t -BuMgCl switched the product to the trans diastereomer. Jonathan W. Burton of the University of Oxford employed (Organic Lett. 2010, 12, 2738) a related oxidative cyclization for the diastereoselective conversion of 19 to 20. E. J. Corey of Harvard University reported (Organic Lett. 2010, 12, 300) a new ligand for the enantioselective Ni-mediated reduction of 21 to 22. Shu-Li You, also of the Shanghai Institute of Organic Chemistry, established (J. Am. Chem. Soc. 2010, 132, 4056) that the alcohol 23, readily prepared by oxidation of p -cresol, could be cyclized to the crystalline 25 in high ee.