945256-29-1Relevant articles and documents
IMPROVED PROCESS FOR PREPARING BORYL 7-AZAINDOLE COMPOUNDS
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Page/Page column 22, (2016/12/22)
The present disclosure relates to an improved process for the preparation of 3-boryl substituted azaindole compounds in high yields and high selectivity. Such azaindole compounds may be used as intermediates to form compounds with cytotoxic, anticancer, and antiviral activities.
Iridium-catalyzed C-H borylation of heteroarenes: Scope, regioselectivity, application to late-stage functionalization, and mechanism
Larsen, Matthew A.,Hartwig, John F.
supporting information, p. 4287 - 4299 (2014/04/03)
A study on the iridium-catalyzed C-H borylation of heteroarenes is reported. Several heteroarenes containing multiple heteroatoms were found to be amenable to C-H borylation catalyzed by the combination of an iridium(I) precursor and tetramethylphenanthroline. The investigations of the scope of the reaction led to the development of powerful rules for predicting the regioselectivity of borylation, foremost of which is that borylation occurs distal to nitrogen atoms. One-pot functionalizations are reported of the heteroaryl boronate esters formed in situ, demonstrating the usefulness of the reported methodology for the synthesis of complex heteroaryl structures. Application of this methodology to the synthesis and late-stage functionalization of biologically active compounds is also demonstrated. Mechanistic studies show that basic heteroarenes can bind to the catalyst and alter the resting state from the olefin-bound complex observed during arene borylation to a species containing a bound heteroarene, leading to catalyst deactivation. Studies on the origins of the observed regioselectivity show that borylation occurs distal to N-H bonds due to rapid N-H borylation, creating an unfavorable steric environment for borylation adjacent to these bonds. Computational studies and mechanistic studies show that the lack of observable borylation of C-H bonds adjacent to basic nitrogen is not the result of coordination to a bulky Lewis acid prior to C-H activation, but the combination of a higher-energy pathway for the borylation of these bonds relative to other C-H bonds and the instability of the products formed from borylation adjacent to basic nitrogen.
A traceless directing group for C - H borylation
Preshlock, Sean M.,Plattner, Donald L.,Maligres, Peter E.,Krska, Shane W.,Maleczka Jr., Robert E.,Smith III, Milton R.
supporting information, p. 12915 - 12919 (2014/01/06)
Not a trace: Borylation of the nitrogen in nitrogen heterocycles or anilines provides a traceless directing group for subsequent catalytic C - H borylation. Selectivities that previously required Boc protection can be achieved; furthermore, the NBpin directing group can be installed and removed in situ, and product yields are substantially higher. Boc=tert-butoxycarbonyl, pin=pinacolato. Copyright
