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1.
Org Lett ; 3(2): 287-9, 2001 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-11430056

RESUMO

[figure: see text] Monosubstituted[2.2]paracyclophanes 3a-c with planar chirality were found to act as chiral initiators in an enantioselective addition of diisopropylzinc to 2-alkynylpyrimidine-5-carbaldehyde 1 to afford 2-alkynylpyrimidyl alkanol 2 with up to 97% ee.

2.
Org Lett ; 3(24): 3851-4, 2001 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-11720552

RESUMO

A new and efficient one-pot system of asymmetric catalysis is presented in which a chiral catalyst (5-pyrimidyl alkanol) self-improves its ee by asymmetric autocatalysis and then acts as a highly enantioselective chiral catalyst for other asymmetric synthesis (addition of dialkylzincs to aldehydes) to provide products (sec-alcohols) with very high ee (up to 99%).[reaction: see text]

4.
Enantiomer ; 6(2-3): 189-92, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11570425

RESUMO

A method is proposed for the determination of the absolute configuration of amino acids with low enantiomeric excesses by using asymmetric autocatalysis of pyrimidyl alkanol with amplification of enantiomeric excess.


Assuntos
Aminoácidos/química , Catálise , Conformação Molecular
5.
Acc Chem Res ; 33(6): 382-90, 2000 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10891056

RESUMO

Asymmetric autocatalysis is a process of automultiplication of a chiral compound in which chiral product acts as a chiral catalyst for its own production. The discovery and the development of asymmetric autocatalysis of pyrimidyl-, quinolyl-, and pyridylalkanols are described in the enantioselective additions of diisopropylzinc to the corresponding nitrogen-containing aldehydes. (Alkynylpyrimidyl)alkanols automultiply with a yield of over 99% and over 99.5% ee. Asymmetric autocatalysts with extremely low ee's automultiply with significant amplification of ee's without the need for any other chiral auxiliaries. Small enantiomeric imbalances of chiral molecules induced by physical factors can be amplified by the present asymmetric autocatalysis.


Assuntos
Álcoois/química , Aminoácidos/síntese química , Álcoois/síntese química , Catálise , Hidroxiquinolinas/química , Ferro , Leucina/química , Conformação Molecular , Compostos Organometálicos/química , Piridinas/química , Estereoisomerismo , Zinco
6.
Chem Rec ; 1(4): 321-32, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11893072

RESUMO

The discovery and development of asymmetric autocatalysis, in which the structures of the chiral catalyst and the chiral product are the same, are described. Chiral 5-pyrimidyl, 3-quinolyl, and 5-carbamoyl-3-pyridyl alkanols act as highly enantioselective asymmetric autocatalysts in the enantioselective addition of diisopropylzinc to the corresponding aldehydes, such as pyrimidine-5-carbaldehyde. 2-Alkynyl-5-pyrimidyl alkanol with an enantiomeric excess (ee) of >99.5% automultiplies practically perfectly as an asymmetric autocatalyst in a yield of >99% and >99.5% ee. Asymmetric autocatalysis with an amplification of ee has thus been realized. Consecutive asymmetric autocatalysis starting with chiral 2-alkynylpyrimidyl alkanol of only 0.6% ee amplifies its ee significantly, and yields itself as the product with >99.5% ee. The reaction of pyrimidine-5-carbaldehyde and diisopropylzinc in the presence of chiral initiators with low ee's, such as secondary alcohol, amine, carboxylic acid, mono-substituted [2.2]paracyclophane, and chiral primary alcohols due to deuterium substitution, regulates the absolute configuration of the resulting pyrimidyl alkanols, and the ee of the resulting pyrimidyl alkanol is much higher than that of the chiral initiator. Leucine and [6]helicene with very low ee's, which are known to be induced by circularly polarized light (CPL), also serve as chiral initiators to produce pyrimidyl alkanol with higher ee's. Overall, the process represents the first correlation between the chirality of CPL and an organic compound with very high ee. Chiral inorganic crystals, such as quartz and sodium chlorate, act as chiral inducers in the asymmetric autocatalysis of pyrimidyl alkanol. The process correlates for the first time ever the chirality of inorganic crystals with an organic compound with very high ee.


Assuntos
Retroalimentação Fisiológica , Modelos Moleculares , Pirimidinas/química , Aldeídos/química , Catálise , Mimetismo Molecular , Estereoisomerismo , Zinco/química
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