Synthesis of (+)-Discodermolide by Catalytic Stereoselective Borylation Reactions
作者:Zhiyong Yu、Robert J. Ely、James P. Morken
DOI:10.1002/anie.201405455
日期:2014.9.1
1990 and, to this day, remains a compelling synthesis target. Not only does the compound possess fascinating biological activity, but it also presents an opportunity to test current methods for chemical synthesis and provides an inspiration for new reaction development. A new synthesis of discodermolide employs a previously undisclosed stereoselectivecatalytic diene hydroboration and also establishes
A New General Route to Acceptor-Substituted Vinyloxiranes via Siloxyoxiranes - Novel Promising Synthetic Building-Blocks
作者:Ernst Schaumann、Frank Tries
DOI:10.1055/s-2002-19796
日期:——
Epoxidation of silylenolethers 2a,b with dimethyldioxirane yields siloxyoxiranes 3a,b. Anions 4a-d lead to nucleophilic ring-opening in the acetal position C-1 of 3 to give diols 5a-d. Monotosylation and cyclisation provide acceptor-substituted vinyloxiranes 6a-d.
Palladium-catalyzed cross-coupling reaction of 2,3-diboryl1,3-butadiene with an alkenyl halide or a dienyl halide allowed us to straightforwardly prepare various kinds of acyclic cross-conjugatedpolyenes that are referred to as dendralenes. The present method is applicable to the synthesis of not only symmetrical [4]- and [6]dendralenes but also unsymmetrical [3]-to [5]dendralenes.
Aromatic Cations from Oxidative Carbon–Hydrogen Bond Cleavage in Bimolecular Carbon–Carbon Bond Forming Reactions
作者:Dane J. Clausen、Paul E. Floreancig
DOI:10.1021/jo301185h
日期:2012.8.3
with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) to form persistent aromatic oxocarbenium ions through oxidative carbon–hydrogen cleavage. This process is tolerant of electron-donating and electron-withdrawing groups on the benzene ring and additional substitution on the pyran ring. A variety of nucleophiles can be added to these cations to generate a diverse set of structures.