A Stereoselective Synthesis of<i>trans</i>-1,2-Disubstituted Alkenes Based on the Condensation of Aldehydes with Metallated 1-Phenyl-1<i>H</i>-tetrazol-5-yl Sulfones
作者:Paul R. Blakemore、William J. Cole、Philip J. Kocieński、Andrew Morley
DOI:10.1055/s-1998-1570
日期:1998.1
The reaction of metallated 1-phenyl-1H-tetrazol-5-yl sulfones and aldehydes gives good yields and stereoselectivity of trans-1,2-disubstituted alkenes when potassium or sodium hexamethyldisilazide is used as base and 1,2-dimethoxyethane is used as solvent.
A new robust methodology for gram-scale iron-catalyzed cross-coupling between alkyl Grignard reagents and alkenyl or aryl halides is developed. This method does not require toxic additives such as NMP or expensive ligands. Its efficiency relies on the use of simple alkoxide magnesium salts as additives. On the basis of these results, a new procedure for one-pot synthesis of substituted benzamides from
Treatment of (E)-alk-1-enyldicyclohexylboranes with tributyltin methoxide in the presence of galvinoxyl (1 mol%) at room temperature results in transfer of the alk-1-enyl group from boron to tin to give (E)-alk-1-enyltributylstannanes in a highlystereoselective fashion. Subsequent halodestannylation of (E)-alk-1-enyltributylstannanes is allowed to proceed in a one-pot manner to produce the corresponding
n-pentyl 1-methyl-1H-tetrazol-5-yl (MT) sulfone 1a in the Julia-Kocienski reactions were compared with those of the PT sulfone 1b and the TBT sulfone 1c. The improved stability of the anion derived from the n-pentyl MT sulfone 1a enhanced the efficiency of the olefination reactions and gave higher yields of the product alkenes 3 compared with the PT sulfone 1b. Especially high E-selectivity and high
The Reactions of (1-Halo-1-alkenyl)dialkylboranes with Lead(IV) Acetate or (Diacetoxyiodo)benzene. A Stereoselective Synthesis of 1-Halo-1,2-dialkylethylenes
作者:Yuzuru Masuda、Akira Arase、Akira Suzuki
DOI:10.1246/bcsj.53.1652
日期:1980.6
The reaction of (1-halo-1-alkenyl)dialkylboranes with lead(IV) acetate or (diacetoxyiodo)benzene was studied. (1-Bromo-1-alkenyl)dialkylboranes gave 1-bromo-1,2-dialkylethylenes. When alkyl groups ...