Microwave-assisted synthesis of the (E)-α-methylalkenoate framework from multifunctionalized allylic phosphonium salts
作者:Lidiane Meier、Misael Ferreira、Marcus M. Sá
DOI:10.1002/hc.21001
日期:——
A convenient and general microwave-assisted method for the synthesis of stereochemicallydefined α-methylalkenoic acids and esters from allylic phosphonium salts in a basic aqueous medium is described. A selective preparation of acids or esters was dependent on the base (NaOH or NaHCO3) employed in the reaction and could be achieved with good to excellent yields under mild conditions in the absence
P(RNCH2CH2)3N: an efficient promoter for the direct synthesis of E-α,β-unsaturated esters
作者:Philip Kisanga、Bosco D'Sa、John Verkade
DOI:10.1016/s0040-4020(01)00782-7
日期:2001.9
Upon reacting ethyl acetate or methyl propionate with a variety of aromatic aldehydes in the presence of 1.06–1.2 equiv. of the pro-azaphosphatranes, P(MeNCH2CH2)3N, P(i-PrNCH2CH2)3N or [P(i-PrNCH2CH2)2(NHCH2CH2)N at 40–50°C for 2–6 h in isobutyronitrile, the corresponding α,β-unsaturated esters were formed as the only products. Ethyl acetate reacts with aldehydes to form exclusively E-isomers while