74684-63-2Relevant academic research and scientific papers
HIGHLY REGIO AND CHEMOSELECTIVE RING OPENING OF EPOXIDES WITH TRIMETHYLSILYL AZIDE IN THE PRESENCE OF ALUMINIUM ISOPROPOXIDE AND TITANIUM ISOPROPOXIDE
Sutowardoyo, Kun I.,Emziane, Mohamed,Lhoste, Paul,Sinou, Denis
, p. 1435 - 1446 (1991)
The ring-opening of functionalized epoxides with trimethylsilyl azide in the presence of a catalytic amount of Ti(O-i-Pr)4 or Al(O-i-Pr)3 is described.The reaction is stereospecific and highly regiospecific, leading generally to the formation of the carbon-azido bond on the less substituted carbon.The mechanism of this reaction is also discussed.
Activation of carboxylic acids in asymmetric organocatalysis
Monaco, Mattia Riccardo,Poladura, Belen,Diaz De Los Bernardos, Miriam,Leutzsch, Markus,Goddard, Richard,List, Benjamin
, p. 7063 - 7067 (2014/07/08)
Organocatalysis, catalysis using small organic molecules, has recently evolved into a general approach for asymmetric synthesis, complementing both metal catalysis and biocatalysis.1 Its success relies to a large extent upon the introduction of novel and generic activation modes.2 Remarkably though, while carboxylic acids have been used as catalyst directing groups in supramolecular transition-metal catalysis,3 a general and well-defined activation mode for this useful and abundant substance class is still lacking. Herein we propose the heterodimeric association of carboxylic acids with chiral phosphoric acid catalysts as a new activation principle for organocatalysis. This self-assembly increases both the acidity of the phosphoric acid catalyst and the reactivity of the carboxylic acid. To illustrate this principle, we apply our concept in a general and highly enantioselective catalytic aziridine-opening reaction with carboxylic acids as nucleophiles. Activation by dimerization: There is still no general activation mode for carboxylic acids in organocatalysis. The formation of heterodimers between chiral phosphoric acid diesters and carboxylic acids can be used to activate and direct reactivity of the latter in asymmetric reactions. This novel principle has been applied to the ring-opening desymmetrization and kinetic resolution of aziridines leading to valuable amino alcohols.
Bronsted acid-catalyzed desymmetrization of meso-aziridines
Rowland, Emily B.,Rowland, Gerald B.,Rivera-Otero, Edwin,Antilla, Jon C.
, p. 12084 - 12085 (2008/04/11)
The enantioselective ring-opening of meso-aziridines with azide nucleophiles proceeded in the presence of a catalytic amount of a chiral phosphoric acid catalyst. The reaction affords the formation of the products in excellent yield and enantioselectivity. Preliminary mechanistic studies indicate that the active catalytic species is a chiral silane that is generated in situ. Copyright
