《Vinylidene Homologation of Boronic Esters and its Application to the Synthesis of the Proposed Structure of Machillene》 was written by Fordham, James M.; Grayson, Matthew N.; Aggarwal, Varinder K.. Product Details of 78782-17-9This research focused onvinylidene homologation boronic ester lithiated epoxysilane; machillene proposed structure synthesis; homologation; natural product; organoboron; stereospecificity; vinyl boronic ester. The article conveys some information:
Alkenyl boronic esters are important reagents in organic synthesis. Herein, we report that these valuable products can be accessed by the homologation of boronic esters with lithiated epoxysilanes [thus, e.g., treatment of epoxysilane I in pentane at -95° with TMEDA/tBuLi followed by addition of boronic ester II in pentane, stirring for 1 h, warming to -78° for an addnl. hour and finally warming to room temperature and then 40° for 1 h afforded III (77%)]. Aliphatic and electron-rich aromatic boronic esters provided vinylidene boronic esters in moderate to high yields, while electron-deficient aromatic and vinyl boronic esters were found to give the corresponding vinyl silane products. Through DFT calculations, this divergence in mechanistic pathway has been rationalized by considering the stabilization of neg. charge in the C-Si and C-B bond breaking transition states. This vinylidene homologation was used in a short six-step stereoselective synthesis of the proposed structure of machillene, however, synthetic and reported data were found to be inconsistent. In the experiment, the researchers used many compounds, for example, Bis[(pinacolato)boryl]methane(cas: 78782-17-9Product Details of 78782-17-9)
Bis[(pinacolato)boryl]methane(cas: 78782-17-9) belongs to organoboron compounds. Organoboron compounds are versatile intermediates and as such are some of the most important classes of reagents in modern organic chemistry. This stems from their ease of preparation combined with their ability to undergo a broad range of chemical transformations.Product Details of 78782-17-9
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