Torquoselectivity in the Nazarov Reactions of Allenyl Vinyl Ketones
作者:Timothy D. R. Morgan、Luc M. LeBlanc、Giselle H. Ardagh、Russell J. Boyd、D. Jean Burnell
DOI:10.1021/jo502532a
日期:2015.1.16
Nazarov reactions mediated by BF3-etherate of a series of carbon-substituted allenyl vinyl ketones provided intermediates in which substituents on the termini of the allenes had rotated away from the vinyl moieties, and these intermediates were trapped by (4 + 3)-cyclizations. A computational examination of the torquoselectivity of these Nazarov reactions confirmed a kinetic preference for the observed
Intramolecular Diels−Alder Reactions of Optically Active Allenic Ketones: Chirality Transfer in the Preparation of Substituted Oxa-Bridged Octalones
作者:Michael E. Jung、Sun-Joon Min
DOI:10.1021/ja052771e
日期:2005.8.1
reaction of allenic ketones containing a furyl unit (IMDAF) to generate oxatricyclic systems in good yields is described. The alkene dienophiles 1ab give poor yields of the cycloadducts 2ab, presumably due to the facile retro Diels-Alder reaction. However, the analogous allenic dienophile 7 afforded the desired cycloadduct 8 in 91% yield on treatment with dimethylaluminum chloride. When the allene bears
N-2,3-alkadienyldiphenylmethanimines 5a-h are formed in moderate yields in 1,3-substitution reactions (SN2′) of propargylic sulfonates with an organocopper reagent derived from metalated N-methyldiphenylmethanimine 1 and Me2S·CuBr. The imines can be readily hydrolyzed to primary α-allenic amines. Alkylation of the imines with methyl fluorosulfonate followed by hydrolysis gives N-methyl-subsituted secondary
Highly Stereoselective Palladium-Catalyzed Dithiocarbonylation of Propargylic Mesylates with Thiols and Carbon Monoxide
作者:Wen-Jing Xiao、Howard Alper
DOI:10.1021/jo047938l
日期:2005.3.1
propargylic mesylates with thiols and carbon monoxide has been developed by the use of tetrakis(triphenylphosphine)palladium(0) as the catalyst at 90 °C in THF. The reaction affords the corresponding dithioesters in good to excellent yields. For some secondary and tertiary propargylic alcohols with a terminal or internal triple bond, the reaction stereoselectively produces E-dithioesters as products. The dithiocarbonylation
Amination and [2,3]-sigmatropic rearrangement of propargylic sulfides using a ketomalonate-derived oxaziridine: synthesis of N-allenylsulfenimides
作者:Alan Armstrong、Richard S. Cooke、Stephen E. Shanahan
DOI:10.1039/b307722e
日期:——
Amination of propargylic sulfides with a ketomalonate-derived oxaziridine under metal free conditions gives N-Boc-N-allenylsulfenimides via [2,3]-sigmatropicrearrangement.