English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Pd-catalyzed carboxylic acid guided regioselective alkynylation of cage B(4)-H bonds in o -carboranes has been achieved for the first time using two different catalytic systems. In the presence of 5 mol% Pd(OAc) 2 and 3 equiv. of AgOAc, the reaction of 1-COOH-2-R 1 -C 2 B 10 H 10 with R 3 SiC[triple bond, length as m-dash]CBr in ClCH 2 CH 2 Cl gives 4-(R 3 SiC[triple bond, length as m-dash]C)-2-R 1 - o -C 2 B 10 H 10 in moderate to high yields. This reaction is compatible with alkynes possessing sterically bulky silyl groups such as i Pr 3 Si or  t  BuMe 2 Si. Meanwhile, another catalytic system of Pd(OAc) 2 /AgOAc/K 2 HPO 4 can catalyze the direct B(4)-alkynylation of 1-COOH-2-R 1 -C 2 B 10 H 10 with terminal alkynes R 2 C[triple bond, length as m-dash]CH in moderate to high yields. The latter has a broader substrate scope from bulky silyl to aromatic to carboranyl substituents. Desilylation of the resultant products affords carboranyl acetylene 4-(HC[triple bond, length as m-dash]C)-2-R 1 - o -C 2 B 10 H 10 which can undergo further transformations such as Sonogashira coupling, dimerization and click reactions. It is suggested that the above two catalytic systems may proceed via Pd(ii)-Pd(iv)-Pd(ii) and Pd(ii)-Pd(0)-Pd(ii) catalytic cycles, respectively. In addition, the silver salt is found to promote the decarboxylation reaction and thereby controls the mono-selectivity.

Palladium catalyzed regioselective B–C(sp) coupling via direct cage B–H activation: synthesis of B(4)-alkynylated o-carboranes