1.Peptide-catalyzed regio- and enantioselective reduction of α,β,γ,δ-unsaturated aldehydes.
Akagawa K1, Sen J, Kudo K. Angew Chem Int Ed Engl. 2013 Oct 25;52(44):11585-8. doi: 10.1002/anie.201305004. Epub 2013 Sep 5.
A resin-supported peptide catalyst (see box in the scheme) was used in the title reaction. The inherent regioselectivity was overcome by the peptide catalyst to promote the 1,6-selective reaction prior to 1,4-reduction. High stereoconvergence was also achieved when using a mixture of geometric isomers of the starting aldehydes. Ach=1-amino-1-cyclohexanecarboxylic acid.
2.Kinetics and mechanism of decomposition of N-chloroamino acids. II: conformationally restricted models.
Awad R1, Hussain A, Crooks PA. J Pharm Sci. 1990 Dec;79(12):1121-2.
The kinetics of decomposition of the following conformationally restricted N-chloro-alpha-amino acids were studied: 1-amino-1-cyclopentanecarboxylic acid (2), 1-amino-1-cyclohexanecarboxylic acid (4), 2-amino-2-norbornanecarboxylic acid (6), and 2-amino-2-benzonorbornanecarboxylic acid (8). The first-order rate constants obtained were 0.520, 5.197, 0.198, and 0.078, respectively, which correlated with the ring strain in the structurally related cyclic ketones cyclopentanone, cyclohexanone, norborane-2-one, and benzonorbornane-2-one. The data are supportive of a concerted mechanism for the decomposition reaction involving an imine-like transition state.
