A samarium‐mediated novel synthesis of enantiopure 4‐amino‐1,3‐diols is carried out through a samarium‐promoted aldol–Tishchenkoreaction starting from chiral α′‐amino‐α‐chloro ketones (derived from natural α‐amino acids) and aldehydes. The process takes place with moderate levels of stereoselectivity and in high yields. A mechanism is proposed to explain these results while the absolute configuration
High Diastereoselective Synthesis of Threo or Erythro Aminoalkyl Epoxides from .alpha.-Amino Acids
作者:Jose Barluenga、Beatriz Baragana、Jose M. Concellon
DOI:10.1021/jo00126a019
日期:1995.10
alpha-Chloro-alpha'-(dibenzylamino) methylketones 3 are synthesized in enantiomerically pure form starting from alpha-amino acids. Reduction of amino ketones 3 and further epoxidation affords three aminoalkyl epoxides 6 with diastereoisomeric excess ranging between 94% and 98%. The synthesis of erythro amino epoxides 9 is also described by reaction of alpha-amino aldehydes 7 with in situ generated (halomethyl)lithium. Amino epoxides 9 were obtained with a diastereoisomeric excess ranging between 91% and 98%.
The First Synthesis of Enantiopure α-Amino Ketimines and Amino Aziridines
作者:José M. Concellón、Pablo L. Bernad、Estela Riego、Santiago García-Granda、Ángela Forcén-Acebal
DOI:10.1021/jo005741x
日期:2001.4.1
Chiral l-aminoalkyl chloromethyl ketimines 2 are synthesized in enantiomerically pure form starting from l-aminoalkyl chloromethyl ketones 1 and different amines. Reduction of amino ketimines 2 and subsequent spontaneus cyclization affords aminoalkyl aziridines 3 with high diastereoisomeric excess and without detectable racemization.
Synthetic Applications of 1-Aminoalkyl Chloromethyl Ketones. Synthesis of Enantiopure 3-Azetidinols and Aminoalkyl Epoxides
作者:José Barluenga、Beatriz Baragaña、José M. Concellón
DOI:10.1021/jo9700585
日期:1997.8.1
Addition of several organocerium compounds to chiral 1-aminoalkyl chloromethyl ketones 1 affords, after deprotection, enantiomerically pure 3-azetidinols 5. The synthesis of enantiopure amino epoxides 8 is also described by successive treatment of chiral alpha-amino ketones 1 with organocerium compounds and methyllithium.
Preparation and Synthetic Applications of Enantiopure (2<i>S</i>,3<i>S</i>)- or (2<i>R</i>,3<i>S</i>)-2-Halomethyl-1,2-epoxyalkan-3-amines
作者:José Barluenga、Beatriz Baragaña、José M. Concellón
DOI:10.1021/jo9823590
日期:1999.4.1
Enantiomerically pure (2S,3S)-3 and its diastereoisomer (2R,3S)-2-halomethyl-1,2-epoxyalkan-3-amine 4 have been obtained from 1-aminoalkyl halomethyl ketones 1 and (iodomethyl)lithium or (chloromethyl)lithium, respectively. Some synthetic applications of compounds 3 are described: chiral unsaturated 1,3-aminoalcohols 8 or 2-(halomethylidene)-3-(dibenzylamino)-alkan-1-ol 11 is obtained from 3 by halogeno-lithium or by hydrogen-lithium exchange, respectively. Transformation of 8c into its methyl ester derivative 9c is also reported.