C-Glycosides and C-disaccharide precursors through carbonylative Stille coupling reactions
作者:Vincent Jeanneret、Lieven Meerpoel、Pierre Vogel
DOI:10.1016/s0040-4039(96)02367-2
日期:1997.1
Under CO atmosphere and in the presence of Pd2(dba)3 and Ph3As a suitably protected 1-stannylglucal derivative could be carbonylated and coupled to 5-bromo-7-oxabicyclo[2.2.1]hept-5-en-2-yl derivatives. The carbonylative Stille coupling was also successful between 1-iodoglucals and tributyl(vinyl)stannane or tributyl(fur-2-yl)stannane. A cross-conjugated dienone was also obtained through coupling of
Polar vs steric effects in the 1,3-dipolar cycloaddition reactions of acetonitrile oxide and 2-endO-acetoxy-5-halo-7-oxabicyclo[2.2.1]hept-5-en-2-exo-carbonitrile
作者:Odön Arjona、Alfonso de Dios、Roberto Fernandez de la Pradilla、Araceli Mallo、Joaquin Plumet
DOI:10.1016/s0040-4020(01)81474-5
日期:——
The regioselectivity of the cycloaddition reactions between acetonitrile oxide and a number of 7-oxabicyclo[ 2.2.1]hept-5-enes is discussed. Acetonitrile oxide adds with complete regioselectivity to 2-endo-acetoxy-5-halo-7-oxabicyclo[2.2.1]hept-5-en-2-exo-carbonitriles. Kinetic measurements indicate a more polar transition state for 2a than for the unsubstituted substrate la
Control of the Regioselectivity in the Pauson−Khand Reaction of 7-Oxanorbornene Derivatives
作者:Odón Arjona、Aurelio G. Csákÿ、M. Carmen Murcia、Joaquín Plumet
DOI:10.1021/jo9903095
日期:1999.10.1
The regiochemistry of the Pauson-Khand reaction of 7-oxanorbornene derivatives can be influenced by a remote substituent at carbon C-2. Furthermore, a remarkable effect on the regiochemical outcome of this reaction was observed by halide substituents in the olefin carbons, which may be utilized as an element of control of regioselectivity.