1029801-32-8Relevant articles and documents
Difunctionalization of C?C σ?Bonds Enabled by the Reaction of Bicyclo[1.1.0]butyl Boronate Complexes with Electrophiles: Reaction development, scope, and stereochemical origins
Bennett, Steven H.,Fawcett, Alexander,Denton, Elliott H.,Biberger, Tobias,Fasano, Valerio,Winter, Nils,Aggarwal, Varinder K.
, p. 16766 - 16775 (2020)
Difunctionalization reactions of C?C σ-bonds have the potential to streamline access to molecules that would otherwise be difficult to prepare. However, the development of such reactions is challenging because C?C σ-bonds are typically unreactive. Exploiting the high ring-strain energy of polycyclic carbocycles is a common strategy to weaken and facilitate the reaction of C?C σ-bonds, but there are limited examples of highly strained C?C σ-bonds being used in difunctionalization reactions. We demonstrate that highly strained bicyclo[1.1.0]butyl boronate complexes (strain energy ca. 65 kcal/mol), which were prepared by reacting boronic esters with bicyclo[1.1.0]butyl lithium, react with electrophiles to achieve the diastereoselective difunctionalization of the strained central C?C σbond of the bicyclo[1.1.0]butyl unit. The reaction shows broad substrate scope, with a range of different electrophiles and boronic esters being successfully employed to form a diverse set of 1,1,3-trisubstituted cyclobutanes (>50 examples) with high diastereoselectivity. The high diastereoselectivity observed has been rationalized based on a combination of experimental data and DFT calculations, which suggests that separate concerted and stepwise reaction mechanisms are operating, depending upon the migrating substituent and electrophile used.
