Asymmetric desymmetrization of the diallyl acetals of alkynal (1) by an enantioselective Pauson–Khand-type reactioncatalyst was studied. The corresponding 5-oxabicyclo[3.3.0]octenones (2) were obtained as a mixture of diastereomers (2a and 2b), which were hydrolyzed to afford a single enantiomer (3), in high yields (up to 88%) as well as excellent enantioselectivities (up to 97%).
Reaction of 2-bromo-2-phenyl-1,1-dichlorocyclopropane with phenols and alcohols
作者:E. K. Kurbankulieva、A. N. Kazakova、S. S. Zlotskii
DOI:10.1134/s0012500812080022
日期:2012.8
recently that substituted gem dichloro cyclopropanes in the reactions with monohydric and dihydric phenols convert at the first stage to com pounds with exocyclic double bond. The latter, owing to the presence of the reactive chloroallyl moiety, readily react with hydroxy groups to form the corre sponding cyclopropanone ketals [1]. It was interesting to study the transformations under these conditions
Synthesis and claisen rearrangement of 1-allyloxy-1-carbomethoxy allenes
作者:M.J. Sleeman、G.V. Meehan
DOI:10.1016/s0040-4039(00)99240-2
日期:1989.1
A number of allyl allenyl ethers (1) have been synthesised and shown to undergo the Claisenrearrangement. The kinetics of rearrangement of (1b) together with stereochemical data obtained, is consistent with a concerted mechanism for these rearrangements.