Synthesis of novel axially chiral Rh–NHC complexes derived from BINAM and application in the enantioselective hydrosilylation of methyl ketones

Abstract

Novel axially chiral Rh N-heterocyclic carbene complexes were prepared from axially dissymmetric 1,1'-binaphthalenyl-2,2'-diamine and applied in the Rh-catalyzed enantioselective hydrosilylation of methyl ketones. The corresponding sec-alcohols can be obtained in high yields with good to excellent ee.

Heterocyclic Carbenes: Synthesis and Coordination Chemistry

“…The dinuclear silver and copper complexes with the tetracarbene ligand derived from 104 have also been described. [343] The lutidine-bridged tetraimidazolium salt 106 (Scheme 61) forms mono (207) and dinuclear (208) complexes with silver(I) depending on the amount of silver salt used in the synthesis. As expected, these silver complexes are excellent carbenetransfer agents and thus have been used for the preparation of [194a] The tetraimidazolium salt 106 contains, in contrast to 104, two additional pyridine donor functions which in principle allow the preparation of endocyclic dinuclear double-pincer complexes (Scheme 57).…”

Preparation of novel axially chiral NHC–Pd(II) complexes and their application in oxidative kinetic resolution of secondary alcohols

“…As show in Scheme 1, starting from optically active (R)-1,1-binaphthalenyl-2,2 -diamine 2 [(R)-BINAM] and following our previously reported procedures, [6] we can easily obtain the compounds 4-6 in good yields. The detailed spectroscopic data of 4-6 are summarized in the Supporting Information.…”

“…The bond lengths of Pd-C(1) and Pd-C(8) [1.9846(3) and 2.004(5) Å in complex 1a as well as Pd-C(1) = 1.997 (8) and Pd-C(8) = 2.008(7) in complex 1b] are comparable to those of analogs. [7] Selected bond distances (Å) and angles (deg) of (NHC)-Pd(II) complex 1a Bond distances Bond angles Pd-C(1) = 1.984 (6) C ( Selected bond distances (Å) and angles (deg) of (NHC)-Pd(II) complex 1b Bond distances Bond angles Pd-C(1) = 1.997 (8) C (6) www. Next, the enantioselective oxidative kinetic resolution of 1-phenylethanol 8a (racemate) was evaluated using chiral NHC-Pd(II) complex 1b in the presence of various bases and solvents.…”

“…Axially chiral NHC-Pd(II) complexes 1a-d were prepared by using similar procedures to those used for complexes A and B. [5] Compound 4 [6] A red solid; m.p. 202.…”

A stable dimeric mono-coordinated NHC-Pd(II) complex: synthesis, characterization, and reactivity in Suzuki-Miyaura cross-coupling reaction

“…The application of NHC-Pd(II) complex 6 as a catalyst for the Suzuki-Miyaura cross-coupling reaction was examined where both base and solvent effects were carefully examined in the reaction of phenylboronic acid with bromobenzene under ambient atmosphere (we have previously reported the synthesis of a stable axially chiral NHC-Rh(III) complex bearing the same benzimidazolin-2-ylidene moiety and its application in the enantioselective hydrosilylation of methyl ketones 63,64 ). The results are summarized in Tables 1 and 2.…”