- Catalytic asymmetric propargyl- and allylboration of hydrazonoesters: a metal-free approach to sterically encumbered chiral α-amino acid derivatives
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A new asymmetric catalytic propargyl- and allylboration of hydrazonoesters is reported. The reactions utilize allenyl- and allylboronic acids in the presence of the inexpensive parent BINOL catalyst. The reactions can be performed under mild conditions (0 °C) without any metal catalyst or other additives affording sterically encumbered chiral α-amino acids. This is the first metal-free method for the asymmetric propargyl- and allylboration of hydrazonoesters.
- Jonker, Sybrand J. T.,Diner, Colin,Schulz, G?ran,Iwamoto, Hiroaki,Eriksson, Lars,Szabó, Kálmán J.
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- Synthesis of amino-diamondoid pharmacophores: Via photocatalytic C-H aminoalkylation
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We report a direct C-H aminoalkylation reaction using two light-activated H-atom transfer catalyst systems that enable the introduction of protected amines to native adamantane scaffolds with C-C bond formation. The scope of adamantane and imine reaction partners is broad and deprotection provides versatile amine and amino acid building blocks. Using readily available chiral imines, the enantioselective synthesis of the saxagliptin core and rimantadine derivatives is also described.
- Weigel, William K.,Dang, Hoang T.,Yang, Hai-Bin,Martin, David B. C.
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supporting information
p. 9699 - 9702
(2020/09/03)
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- Asymmetric Br?nsted acid catalyzed cycloadditions-efficient enantioselective synthesis of pyrazolidines, pyrazolines, and 1,3-diamines from N-acyl hyrazones and alkenes
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A general, metal-free, highly enantioselective Bronsted acid catalyzed [3+2] cycloaddition between hydrazones and alkenes has been developed that affords pyrazolidine derivatives (see scheme). The resulting optically active pyrazolidines can undergo many chemical transformations which allow, for example, the enantioselective synthesis of valuable pyrazolines and 1,3-diamines. Copyright
- Rueping, Magnus,Maji, Modhu Sudan,Kü?ük, Hatice Ba?pínar,Atodiresei, Iuliana
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supporting information
p. 12864 - 12868
(2013/02/22)
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