- Bronsted acid accelerated Pd-catalyzed direct asymmetric allylic alkylation of azlactones with simple allylic alcohols: A practical access to quaternary allylic amino acid derivatives
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A Bronsted acid accelerated Pd-catalyzed asymmetric allylic alkylation of azlactones with simple allylic alcohols under mild reaction conditions has been realized, which provides a direct and readily scalable approach for the synthesis of all-carbon quaternary allylic amino acid derivatives in excellent yields and good enantioselectivities. (Chemical Equation Presented).
- Zhou, Hui,Yang, Huameng,Liu, Muwen,Xia, Chungu,Jiang, Gaoxi
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supporting information
p. 5350 - 5353
(2015/01/09)
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- Bispalladacycle-catalyzed Michael addition of in situ formed azlactones to enones
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The development and further evolution of the first catalytic asymmetric conjugate additions of azlactones as activated amino acid derivatives to enones is described. Whereas the first-generation approach started from isolated azlactones, in the second-generation approach the azlactones could be generated in situ starting from racemic N-benzoylated amino acids. The third evolution stage could make use of racemic unprotected α-amino acids to directly form highly enantioenriched and diastereomerically pure masked quaternary amino acid products bearing an additional tertiary stereocenter. The step-economic transformations were accomplished by cooperative activation by using a robust planar chiral bis-Pd catalyst, a Br?nsted acid (HOAc or BzOH; Ac=acetyl, Bz=benzoyl), and a Br?nsted base (NaOAc). In particular the second- and third-generation approaches provide a rapid and divergent access to biologically interesting unnatural quaternary amino acid derivatives from inexpensive bulk chemicals. In that way highly enantioenriched acyclic α-amino acids, α-alkyl proline, and α-alkyl pyroglutamic acid derivatives could be prepared in diastereomerically pure form. In addition, a unique way is presented to prepare diastereomerically pure bicyclic dipeptides in just two steps from unprotected tertiary α-amino acids. Flourishing step economy: The evolution of the catalytic asymmetric addition of azlactones to enones is described. The first-generation approach started from isolated azlactones. In the second-generation approach azlactones could be generated in situ from racemic N-benzoylated amino acids. The third evolution stage could directly use racemic unprotected α-amino acids to form a large number of highly enantioenriched quaternary amino acids derivatives (see figure). Copyright
- Weber, Manuel,Jautze, Sascha,Frey, Wolfgang,Peters, René
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supporting information
p. 14792 - 14804
(2013/01/15)
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- PYRROLONE MELANIN CONCENTRATING HORMONE RECEPTOR-1 ANTAGONISTS
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The present application provides compounds, including all stereoisomers, solvates, prodrugs and pharmaceutically acceptable forms thereof according to Formula I wherein R1, Formula Ia, R4, R5, Formula Ib, R3, R3a, W, D, R2a, R2b and R2c are defined herein. Additionally, the present application provides pharmaceutical compositions containing at least one compound according to Formula I and optionally at least one additional therapeutic agent. Finally, the present application provides methods for treating a patient suffering from an MCHR-1 modulated disease or disorder such as, for example, obesity, diabetes, depression, anxiety or intestinal inflammation, by administration of a therapeutically effective dose of a compound according to Formula I.
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Page/Page column 112
(2010/04/28)
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- 1-Azadienes in Heterocyclic Synthesis. Reaction of 1-N-Alkyl-1-azapenta-1,3-dienes with Mesoionic Oxazolones
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1-N-Alkyl-1-azapenta-1,3-dienes 2 smoothly reacted with various mesoionic oxazolones 1 to afford 3,4-dihydro-2-pyridones 3 in excellent yields and there is no evidence for the formation of any products arising from the cycloaddition on the carbon-carbon double bond or on the azomethine function.
- Sain, B.,Sandhu, J. S.
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p. 1007 - 1010
(2007/10/02)
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