134964-69-5Relevant articles and documents
Synthesis of optically active azetidine-2,4-dicarboxylic acid and related chiral auxiliaries for asymmetric synthesis
Hoshino, Jun'ichi,Hiraoka, Junko,Hata, Yasuo,Sawada, Seiji,Yamamoto, Yukio
, p. 693 - 698 (2007/10/02)
(S)-1-Phenylethylamine has been used as a chiral auxiliary as well as a nitrogen atom donor in the synthesis of an enantiomeric pair of azetidine-2,4-dicarboxylic acids, the absolute configuration of one of which has been assigned on the basis of the X-ra
On the use of C2-symmetric aziridines as chiral auxiliaries
Tanner,Birgersson,Gogoll,Luthman
, p. 9797 - 9824 (2007/10/02)
A systematic study has been made of the utility of readily available C2-symmetric aziridines as auxiliaries for asymmetric alkylation and aldol reactions of amide enolates. Aziridines with suitably placed oxygen atoms in the side chains proved to be useful for alkylation reactions (d.e. values up to >98%) and the results are explained in terms of an intramolecularly chelated Z-enolate species, which could be observed directly by means of NMR spectroscopy. In contrast, aziridine auxiliaries lacking side-chain oxygens performed better in aldol reactions (syn selectivity up to 98% d.e.) for which a Zimmerman-Traxler transition state is proposed. After reaction, the axuiliaries can be cleaved off non-destructively under mild conditions to afford either optically pure aldehydes or carboxylic acids.
C2-Symmetric Aziridines as Efficient Chiral Auxiliaries
Tanner, David,Birgersson, Carin
, p. 2533 - 2536 (2007/10/02)
The C2-symmetric aziridines 1 and 1' (available from (+)- and (-)-tartaric acid, respectively) are excellent chiral auxiliaries for asymmetric alkylation and aldol reactions.