4-trans-Amino-proline based di- and tetrapeptides as organic catalysts for asymmetric C–C bond formation reactions

Water‐Compatible Iminium Activation: Organocatalytic Michael Reactions of Carbon‐Centered Nucleophiles with Enals

“…[12] At the outset, the conjugate addition of nitromethane to enals was selected to study the catalysts. [13] Despite the interest of the resulting adducts as intermediates in synthesis, [14] enantioselective versions of this reaction have been hardly developed, [15] presumably because of the undesired competing 1,2-addition process. In particular, by this approach an atom-economic route to a-unsubstituted gamino acids, which exhibit potent activity on the central nervous system, [16] would be made feasible in a concise and practical fashion.…”

One-pot synthesis of (R)-convolutamydine A involving in situ chiral organocatalyst formation

“…Following our previous work on organocatalytic aldol reactions [18,19] and applying our expertise in the research fields of the organocatalytic construction of quaternary carbon centers [20][21][22] we decided to study the direct aldol reaction of acetone with 4,6-dibromoisatin. Since amino alcohols 2a and 2b have already been reported by one of us as active external catalysts for the aldol addition of acetone to 4,6-dibromoisatin (entries 1 and 2, Table 1) [15], we were interested in exploring whether selected amino alcohols 2c-2f would perform as well as or even better than catalysts 2a and 2b in the same aldol addition.…”

Recent Advances in Asymmetric Organocatalytic 1,4‐Conjugate Additions

“…Subsequently we demonstrated [8,9] that an asymmetric version of the addition of different nitro alkanes to cyclic enones can be successfully achieved with short peptides based on 4-trans-aminoproline as catalysts (Scheme 1). In the presence of the di-, tri-, and/or tetrapeptide as the catalyst (2 mol-%) and trans-2,5-dimethylpiperazine as an additive, the products have been formed in up to 100 % yield and with up to 88 % ee.…”