1201898-74-9Relevant academic research and scientific papers
Tertiary alkylations of aldehydes, ketones or imines using benzylic organoboronates and a base catalyst
Nagao, Kazunori,Nakamura, Kei,Ohmiya, Hirohisa,Sato, Yukiya,Yabushita, Kenya
supporting information, p. 1065 - 1069 (2020/11/09)
The KHMDS-catalyzed tertiary alkylation of aldehydes, ketones or imines using tertiary benzylic organoboronates is reported. This protocol permitted the use of tertiary benzylic alkylboronates as the tertiary alkyl anion for construction of highly congested contiguous sp3 carbon centers. The mild and transition-metal-free reaction conditions are attractive features of the protocol.
Stereocontrolled synthesis of adjacent acyclic quaternary-tertiary motifs: Application to a concise total synthesis of (-)-filiformin
Blair, Daniel J.,Fletcher, Catherine J.,Wheelhouse, Katherine M. P.,Aggarwal, Varinder K.
, p. 5552 - 5555 (2014/06/10)
Lithiation/borylation methodology has been developed for the synthesis of acyclic quaternary-tertiary motifs with full control of relative and absolute stereochemistry, thus leading to all four possible isomers of a stereodiad. A novel intramolecular Zweifel-type olefination enabled acyclic stereocontrol to be transformed into cyclic stereocontrol. These key steps have been applied to the shortest enantioselective synthesis of (-)-filiformin to date (9 steps) with full stereocontrol. True to (fili)form: Lithiation/borylation methodology has been developed for the synthesis of acyclic quaternary-tertiary motifs with full control of relative and absolute stereochemistry, thus leading to all four possible isomers of a stereodiad. A novel intramolecular Zweifel-type olefination enabled acyclic stereocontrol to be transformed into cyclic stereocontrol. These key steps were applied to the enantioselective synthesis of (-)-filiformin.
Protodeboronation of tertiary boronic esters: Asymmetric synthesis of tertiary alkyl stereogenic centers
Nave, Stefan,Sonawane, Ravindra P.,Elford, Tim G.,Aggarwal, Varinder K.
, p. 17096 - 17098 (2011/03/01)
While tertiary boranes undergo efficient protodeboronation with carboxylic acids, tertiary boronic esters do not. Instead, we have discovered that CsF with 1.1 equiv of H2O (on tertiary diarylalkyl boronic esters) or TBAF?3H2O (on tertiary aryldialkyl boronic esters) effect highly efficient protodeboronation of tertiary boronic esters with essentially complete retention of configuration. Furthermore, substituting D2O for H2O provides ready access to deuterium-labeled enantioenriched tertiary alkanes. The methodology has been applied to a short synthesis of the sesquiterpene, (S)-turmerone.
Improved method for the conversion of pinacolboronic esters into trifluoroborate salts: facile synthesis of chiral secondary and tertiary trifluoroborates
Bagutski, Viktor,Ros, Abel,Aggarwal, Varinder K.
supporting information; experimental part, p. 9956 - 9960 (2010/02/27)
A general method for the preparation of virtually any potassium trifluoroborate salt from the corresponding pinacolboronic ester is reported. Thus, conditions for an azeotropic removal of pinacol from the reaction mixture were found to afford the desired potassium trifluoroborates of sufficient purity (>95%) in nearly quantitative yields irrespective of the nature of the product. The utility of this method is illustrated by the preparation of a broad range of enantioenriched secondary and tertiary potassium trifluoroborates.
