Several elegant methods for the enantioselective transformation of preformed prochiral rings have been put forward. Derek R. Boyd of Queen’s University, Belfast devised (Chem. Commun. 2008, 5535) a Cu catalyst that effected allylic oxidation of cyclic alkenes such as 1 with high ee. Christoph Jaekel of the Ruprecht-Karls-Universität Heidelberg established (Adv. Synth. Cat. 2008, 350, 2708) conditions for the enantioselective hydrogenation of cyclic enones such as 3. Marc L. Snapper of Boston College developed (Angew. Chem. Int. Ed. 2008, 47, 5049) a Cu catalyst for the enantioselective allylation of activated cyclic enones such as 5. Alexandre Alexakis of the University of Geneva showed (Angew. Chem. Int. Ed. 2008, 47, 9122) that dienones such as 8 could be induced to undergo 1,4 addition, again with high ee. Tsutomu Katsuki of Kyushu University originated (J. Am. Chem. Soc. 2008, 130, 10327) an Ir catalyst for the addition of diazoacetate 11 to alkenes such as 10 to give the cyclopropane 12 with high chemo-, enantio- and diastereoselectivity. Weiping Tang of the University of Wisconsin found (Angew. Chem. Int. Ed. 2008, 47, 8933) a silver catalyst that rearranged cyclopropyl diazo esters such as 13 to the cyclobutene 14 with high regioselectivity. Zhang-Jie Shi of Peking University demonstrated (J. Am. Chem. Soc. 2008, 130, 12901) that under oxidizing conditions, a Pd catalyst could cyclize 15 to 16. Sergio Castillón of the Universitat Rovira i Virgili, Tarragona devised (Organic Lett. 2008, 10, 4735) a Rh catalyst for the enantioselective cyclization of 17 to 18. Virginie Ratovelomanana-Vidal of the ENSCP Paris and Nakcheol Jeong of Korea University established (Adv. Synth. Cat. 2008, 350, 2695) conditions for the enantioselective intramolecular Pauson-Khand cyclization of 19 to give, after hydrolysis, the cyclopentenone 20. Quanrui Wang of Fudan University, Several elegant methods for the enantioselective transformation of preformed prochiral rings have been put forward. Derek R. Boyd of Queen’s University, Belfast devised (Chem. Commun. 2008, 5535) a Cu catalyst that effected allylic oxidation of cyclic alkenes such as 1 with high ee.
Ring-closing-metathesis-based synthesis of annellated coumarins from 8-allylcoumarins