346440-54-8Relevant articles and documents
Asymmetric hydroalkylation of alkynes and allenes with imidazolidinone derivatives: α-alkenylation of α-amino acids
Bauer, Felix,Breit, Bernhard,Khosravi, Hormoz,Panahi, Farhad
, p. 7388 - 7392 (2021)
This work reports a new method for the synthesis of quaternary α-alkenyl substituted amino acids by the enantio- and diastereoselective addition of imidazolidinone derivatives to alkynes and allenes. Further hydrolysis of the imidazolidinone products under acidic conditions afforded biologically relevant amino acid derivatives. This method is geometry-selective (E-isomer), enantio- and diastereoselective, and products were obtained in good to excellent yields. The utility of this new methodology is proved by its operational simplicity and the successful accomplishment of gram-scale reactions. Experimental and computational studies suggest the key role of Li in terms of selectivity and support the proposed reaction mechanism.
UNNATURAL AMINO ACIDS
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Paragraph 00185; 00211, (2018/07/05)
The present invention relates to a process for the preparation compounds of Formula (I): Formula (I) wherein X, Z, Q, Ar, R1, R2, R3 and R4 are each as defined herein. The present invention also relates to processes for the preparation of the compounds of quaternary amino acids and hydantions, to compound of Formula(I), to intermediate compounds of Formula (II), to quaternary amino acid compounds of Formula (III) and to hydantoin compounds of Formula (IV).
Aromatic Interactions in Organocatalyst Design: Augmenting Selectivity Reversal in Iminium Ion Activation
Holland, Mareike C.,Metternich, Jan Benedikt,Daniliuc, Constantin,Schweizer, W. Bernd,Gilmour, Ryan
supporting information, p. 10031 - 10038 (2015/07/07)
Substituting N-methylpyrrole for N-methyindole in secondary-amine-catalysed Friedel-Crafts reactions leads to a curious erosion of enantioselectivity. In extreme cases, this substrate dependence can lead to an inversion in the sense of enantioinduction. Indeed, these closely similar transformations require two structurally distinct catalysts to obtain comparable selectivities. Herein a focussed molecular editing study is disclosed to illuminate the structural features responsible for this disparity, and thus identify lead catalyst structures to further exploit this selectivity reversal. Key to effective catalyst re-engineering was delineating the non-covalent interactions that manifest themselves in conformation. Herein we disclose preliminary validation that intermolecular aromatic (CH-π and cation-π) interactions between the incipient iminium cation and the indole ring system is key to rationalising selectivity reversal. This is absent in the N-methylpyrrole alkylation, thus forming the basis of two competing enantio-induction pathways. A simple L-valine catalyst has been developed that significantly augments this interaction.