An efficient synthesis of 1,3-cyclohexadienes from oxabicyclo[2.2.1]heptenes via tandem ring opening-Peterson elimination reactions
摘要:
Oxabicyclo[2.2.1]heptenes react with PhMe2SiLi or PhMe2SiCu.LiCN to yield 1,3-cyclohexadienes. The reaction pathway is shown to proceed via an addition-elimination-Peterson olefination sequence.
Fesulphos-Palladium(II) Complexes as Well-Defined Catalysts for Enantioselective Ring Opening of Meso Heterobicyclic Alkenes with Organozinc Reagents
作者:Silvia Cabrera、Ramón Gómez Arrayás、Inés Alonso、Juan C. Carretero
DOI:10.1021/ja055692b
日期:2005.12.1
The air-stable and readily available cationic methyl palladium(II) complexes of planarchiral Fesulphos ligands [(Fesulphos)Pd(Me)(PhCN)]+ X- are highlyefficientcatalysts for the alkylative ringopening of oxa- and azabicyclicalkenes with dialkylzinc reagents, showing broad scope with regards to both the bicyclic substrate and the dialkylzinc reagent. Catalyst loading as low as 0.5 mol % is sufficient
Scope of the nickel catalyzed asymmetric reductive ring opening reaction. Synthesis of enantiomerically enriched cyclohexenols
作者:Mark Lautens、Tomislav Rovis
DOI:10.1016/s0040-4020(97)10211-3
日期:1998.2
Subjecting a variety of oxabicyclo[2.2.1]heptenes to diisobutylaluminum hydride (DIBAL-H) in the presence of a catalytic amount of Ni(COD)2 and (R)-BINAP results in a highly enantioselective ring opening to generate cyclohexenols with ee's typically greater than 90%. The scope of this reaction has been delineated and alternative nickel catalysts have been examined which are less sensitive than Ni(COD)2
Total Synthesis of Branimycin: An Evolutionary Approach
作者:Valentin S. Enev、Wolfgang Felzmann、Alexey Gromov、Stefan Marchart、Johann Mulzer
DOI:10.1002/chem.201200257
日期:2012.7.27
The first totalsynthesis of the macrolactone antibioticbranimycin (4) has been described. The key disconnection leads to a cis‐dehydrodecalone core and a polyketide side chain which are connected via organometallic addition. The dehydrodecalone core was targeted via altogether five different approaches featuring various kinds of chiral elements and ring‐closing methodology. In the end the most successful
Convenient Synthesis of meso-Cyclohexa-1,3-dienes by One-Pot Two-Step Deoxygenation of 7-Oxabicyclo[2.2.1]hept-2-enes
作者:Ryo Irie、Tomotsugu Yano、Takashi Fujishima
DOI:10.1055/s-0029-1218618
日期:2010.3
Iron(III) hydroxide oxide was found to be an efficient catalyst for the ring-opening reaction of 5,6-cis-disubstituted 7-oxabicyclo[2.2.1]hept-2-enes with acetyl bromide in dichloromethane at room temperature to give cyclohexene derivatives with leaving groups (acetoxy or bromo groups) disposed on each allylic position. A successive one-pot treatment of the reaction mixture with zinc powder and tetrahydrofuran
Synthesis of Cyclohexenols and Cycloheptenols via the Regioselective Reductive Ring Opening of Oxabicyclic Compounds
作者:Mark Lautens、Shihong Ma、Pauline Chiu
DOI:10.1021/ja964361j
日期:1997.7.1
The reductive ring opening of oxabicycliccompounds has been achieved. While RMgBr/MgBr2 works in a few limited substrates, diisobutylaluminum hydride reacts with oxabicyclic[3.2.1]- and -[2.2.1]alkenes to provide cycloheptenols and cyclohexenols in good yield and in some cases in good regioselectivity. With some substrates further reduction of the alkene was observed which led us to examine transition