Variable Metal Chelation Modes and Activation Sequence in Pd-Catalyzed B–H Poly-arylation of Carboranes

ACS Catalysis, Journal Year: 2021, Volume and Issue: 11(22), P. 14047 - 14057

Published: Nov. 4, 2021

The development of synthetic methods for selective multiple functionalization B–H bonds offers great opportunity in expanding the application potentials carboranes. Herein, regioselective poly-arylation o-, m-, and p-carboranes has been developed by imine-directed, Pd-catalyzed iterative activation. isolation key palladium intermediates early stage late palladation validates distinct chelation-assisted modes at PdII center during activation pathways. In particular, a scarce three-coordinated, T-shaped complex isolated proven to be effective subsequent arylation reaction. Stoichiometric control on catalytic penta-arylation p-carborane led exhaustive mono-, di-, tri-, tetra-, penta-arylated products, which provides rationale that 5-fold proceeds sequence from vertex B(2) B(4), then B(5), finally B(3) B(6). It is steric factor introduced aryl groups affects performance metal selectivity chelation mode. A series cage B(3,4,5,6)-tetra-arylated o-carboranes B(2,3,4,5,6)-penta-arylated m- were synthesized good excellent yields as an unreported type molecular propellers. utility this method also illustrated.

Language: Английский

---

Practical Synthesis of B(9)-Halogenated Carboranes with N-Haloamides in Hexafluoroisopropanol

Inorganic Chemistry, Journal Year: 2022, Volume and Issue: 61(13), P. 5326 - 5334

Published: March 21, 2022

The B(9)-H halogenation of o-carborane and m-carborane was achieved with excellent selectivities in hexafluoroisopropanol (HFIP) under simple reaction conditions: single reagent [trichloroisocyanuric acid (TCCA), tribromoisocyanuric (TBCA) or N-iodosuccinimide (NIS)], catalyst-free, air-/moisture-tolerant, convenient work-up. With this method, a variety 9-halogenated o-carboranes m-carboranes were obtained good to yields broad tolerance functional groups.

Language: Английский

---

Regioselective Nucleophilic Alkylation/Arylation of B–H Bonds in o-Carboranes: An Alternative Method for Selective Cage Boron Functionalization

Journal of the American Chemical Society, Journal Year: 2018, Volume and Issue: 140(48), P. 16423 - 16427

Published: Nov. 15, 2018

A new protocol for regioselective nucleophilic cage B-H substitution in o-carboranes has been proposed that is complementary to the strategies of transition metal catalysis and electrophilic substitution. Magnesium-mediated site-selective B(3,6)-H B(9)-H reactions give a series B(3,6)-dialkylated B(9)-alkylated/arylated high yields. Both steric electronic factors C substituents play crucial roles controlling site selectivity.

Language: Английский

---

Coordination Chemistry of Carborane Clusters: Metal-Boron Bonds in Carborane, Carboranyl, and Carboryne Complexes

Comments on Inorganic Chemistry, Journal Year: 2018, Volume and Issue: 38(3), P. 79 - 109

Published: April 16, 2018

Metalated three-dimensional icosahedral boron clusters often exhibit high chemical and thermal stability relative to their simple borane counterparts thus making them a convenient object study the chemistry of metal-boron bonds. The presence multiple reactive vertices makes carboranes unique ligands with unusual steric electronic requirements. This article summarizes recent developments in coordination neutral {C2B10} carborane focus on interactions. Several bonding modes are discussed, including through bridging B–H··· M interactions, boryl complexes B -M bonds, multimetallic assemblies, BB-carboryne complex containing three-membered (BB)>Ru metallacycle.

Language: Английский

---

Rhodium catalyzed cascade cyclization featuring B–H and C–H activation: one-step construction of carborane-fused N-polyheterocycles

Chemical Science, Journal Year: 2018, Volume and Issue: 9(30), P. 6390 - 6394

Published: Jan. 1, 2018

A novel Rh-catalyzed cascade cyclization featuring both carboranyl B–H and aryl C–H activation has been developed, resulting in the one-pot construction of three new B–C C–C bonds. The isolation structural identification a key intermediate provide solid evidence for reaction mechanism.

Language: Английский

---