An asymmetric approach to the pyrrolizidine ring system via N-acetyl and N-propionyl anion cyclisation processes
作者:Anthony Murray、George R. Proctor、P.John Murray
DOI:10.1016/0040-4039(94)02233-2
日期:1995.1
An efficient route to the pyrrolizidineringsystem has been developed. The method, which uses N-acetyl and N-propionyl anion cyclisation reactions as the key steps has provided the natural pyrrolizidines (−)-(1R, 8S)-1-hydroxy-pyrrolizidine (10), (−)-pyrrolizidin-1-ene-3-one (13), (±)-trachelanthamidine (18) together with a range of 2-methyl substituted pyrrolizidine-3-ones.
Synthesis of pyrrolizidine bases by highly diastereoselective and regioselective catalytic carbon-hydrogen insertion reactions of chiral pyrrolidinediazoacetamides
作者:Michael P. Doyle、Alexey V. Kalinin
DOI:10.1016/0040-4039(96)00056-1
日期:1996.2
Pyrrolizidines, (1S, 8S)-1-hydroxypyrrolizidin-3-one and (−)-heliotridane, have been prepared in high yield from diazoacetamides of 2-substituted-pyrrolidines by carbon-hydrogeninsertion catalyzed by dirhodium(II) tetrakis[methyl 1-acylmidazolidin-2-one-4(S)-carboxylates].
Asymmetric syntheses of functionalized pyrrolizidin-3-ones
作者:Christine Greck、Christine Thomassigny、Géraldine Le Bouc
DOI:10.3998/ark.5550190.0013.821
日期:——
The syntheses of 1and 7-hydroxypyrrolizidin-3-ones are described via asymmetric catalytic hydrogenation or diastereoselective reduction of ketones as key steps. 2,7-Disubstituted pyrrolizidin-3-ones are also prepared. The second chiral center is created using stereoselective electrophilic amination or hydroxylation reactions.
Asymmetric synthesis of (1R,8S)- and (1S,8S)-1-hydroxypyrrolizidin-3-ones from Boc-<scp>L</scp>-prolinal and (S)- and (R)-[(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)Fe(CO)(PPh<sub>3</sub>)(Ac)], respectively
作者:R. Paul Beckett、Stephen G. Davies
DOI:10.1039/c39880000160
日期:——
The aldol reaction between the aluminium enolate derived from (S)-[(η5-C5H5)Fe(CO)(PPh3)(Ac)](S)-(3) and Boc-L-prolinal (S)-(2) gives, after deprotection and decomplexation, (1R,8S)-1-hydroxypyrrolizidin-3-one, (1), while its epimer (1S,8S)-(1) is obtained in a similar way from (R)-(3), the inherent stereocontrol of (2) being overpowered by the iron chiral auxiliary.
An efficient route to the pyrrolizidine ring system via an N-acyl anion cyclisation process
作者:Anthony Murray、George R. Proctor、P.John Murray
DOI:10.1016/0040-4020(96)00049-x
日期:1996.3
An enantioselective route to the pyrrolizidineringsystem has been developed which uses an N-acyl anion cyclisation reaction as the key step. This methodology has provided the natural pyrrolizidines (−)-(1R, 8S)-1-hydroxy-pyrrolizidine 7, (−)-pyrrolizidin-1-ene-3-one 9 and (±)-trachelanthamidine 14. Extension of the process to an N-propionyl substrate provides ready access to a series of 2-methyl