865999-25-3Relevant articles and documents
Stepwise Suzuki?Miyaura Cross-Coupling of Triborylalkenes Derived from Alkynyl?B(dan)s: Regioselective and Flexible Synthesis of Tetrasubstituted Alkenes
Tani, Tomohiro,Takahashi, Naomi,Sawatsugawa, Yuuki,Osano, Mana,Tsuchimoto, Teruhisa
, p. 2427 - 2442 (2021)
Alkenes with three boryl groups of differing reactivities were synthesized and subsequently cross-coupled regioselectively with aryl halides in a stepwise manner to afford tetrasubstituted alkenes. The key triborylalkene is derived from the platinum-catalyzed diboration of alkynyl?B(dan)s with B2(pin)2. Due to excellent regioselectivity and reaction efficiency of each step starting with alkynyl?B(dan)s, tetrasubstituted alkenes with desired carbon frameworks at desired positions can be prepared in high yields. For example, an alkene with four distinct aryl groups, p-MeOC6H4, p-CF3C6H4, p-MeC6H4, and p-NCC6H4, was obtained in 71% overall yield via six steps, starting with the dehydrogenative borylation of p-MeC6H4C≡CH with HB(dan). Moreover, a variety of tetrasubstituted alkenes, including regio- and stereoisomers of the above tetraarylalkene, AIE-active TPTPE and derivatives thereof, and (Z)-tamoxifen, a well-known breast cancer drug, were accessed via the developed strategy. (Figure presented.).
Diborative Reduction of Alkynes to 1,2-Diboryl-1,2-Dimetalloalkanes: Its Application for the Synthesis of Diverse 1,2-Bis(boronate)s
Takahashi, Fumiya,Nogi, Keisuke,Sasamori, Takahiro,Yorimitsu, Hideki
, p. 4739 - 4744 (2019/06/27)
Reduction of alkynes with alkali metals in the presence of B2pin2 results in diboration of alkynes. Distinct from conventional dissolving metal hydrogenations, two carbon-boron bonds and also two carbon-alkali metal bonds can be constructed in one operation to form 1,2-diboryl-1,2-dimetalloalkanes. The 1,2-diboryl-1,2-dimetalloalkanes generated are readily convertible to a wide range of vicinal bis(boronate)s. In particular, oxidation of the 1,2-dianionic species provides (E)-1,2-diborylalkenes, unique anti-selective diboration of alkynes being thus executed.
Iridium-catalyzed diborylation of benzylic C-H bonds directed by a hydrosilyl group: Synthesis of 1,1-benzyldiboronate esters
Cho, Seung Hwan,Hartwig, John F.
, p. 694 - 698 (2014/01/17)
We describe a regioselective diborylation of primary benzylic C-H bonds catalyzed by [Ir(COD)OMe]2 and 4,4′-di-tert-butyl-2,2′- bipyridine (dtbpy). The hydrosilyl group acts as a traceless directing group, providing access to a range of 1,1-benzyldiboronate esters in good yields. Transformations of the 1,1-benzyldiboronate ester products include chemoselective Suzuki-Miyaura cross-couplings and synthesis of tetrasubstituted alkenyl boronate esters.