613666-91-4Relevant articles and documents
Borylative Heterocyclization without Air-Free Techniques
Blum, Suzanne A.,Gao, Chao,Nakao, Shuichi
, p. 10350 - 10368 (2020/09/23)
In contrast to previously reported borylative heterocyclization methods, a reaction here proceeds without air-free techniques to access synthetically useful borylated thiophenes, benzothiophenes, and isocoumarins. A comparison of stability/decomposition rates in air of several catecholboronic ester (Bcat) compounds derived from different heterocycle cores showed a strong dependence on the heterocycle structure. Lessons learned from this comparison were then harnessed for the development of borylative heterocyclization reactions under ambient-atmosphere conditions and with wet solvent. In contrast to literature reports suggesting general moisture sensitivity, a subset of Bcat products resulting from this technique were chromatography-stable and directly isolable, obviating the requirement for an extra synthetic transformation into more stable boron species, such as pinacolboronic esters (Bpin), for isolation. The isolated Bcat products were amenable to various downstream functionalization reactions, including reactions that were not accessible with their better-known Bpin counterparts, showing the complementarity of Bcat reaction partners and expanding their known chemistry. These results suggest the value of conceptual revisitation of substitution and solvent influence on stability and isolability of organo-Bcat compound classes and lay the groundwork for development of additional practical borylative methods in air.
Studies into diastereoselective D?tz benzannulations for the synthesis of axially chiral biaryls
Anderson, James C.,Cran, John W.,King, N. Paul
, p. 7771 - 7774 (2007/10/03)
A series of racemic chiral ortho substituents on 1-phenylhex-1-yne have been found to control the atroposelective formation of a biaryl from D?tz benzannulation with pentacarbonyl(methoxyphenylmethylene)chromium(0). The results show there is a subtle balance between the chiral ortho substituent controlling atroposelectivity with a dr 3-5:1 and allowing benzannulation to proceed in yields of 44-67%.
