Reaction Mechanisms of a Tungsten–Germylyne Complex with One or Two Molecules of Alcohols and Arylaldehydes: A DFT Study

Abstract

The mechanisms for the reactions of a tungsten–germylyne complex with one or two molecules of alcohols and arylaldehydes have been investigated with the aid of density functional theory (DFT). The calculation results show that a germylyne complex 1a [Cp*(CO)2W≡GeC(SiH3)3] (Cp* = pentamethylcyclopentadienyl) reacts with only one molecule of alcohol to give hydrido(alkoxygermylene) complexes through coordination of the alcohol oxygen atom to the electron‐deficient germylyne germanium atom followed by hydrogen‐atom transfer from the oxygen atom to the tungsten atom, whereas 1a reacts with two molecules of arylaldehydes consecutively to lead to base‐stabilized alkoxy(germylene) complexes through C–H bond activation followed by hydrogermylation. In addition, two diastereomers can be formed from the reaction of a tungsten–germylyne complex with benzaldehyde. The interconversion of two diastereomers is involved in the consecutive decoordination of the C(O)Ph ligand, rotation of the germylene ligand, and recoordination of the C(O)Ph ligand to the germanium center. Our calculations are consistent with experimental observations and could provide new insights into the reactivity of the germylyne complex.

C–H and H–H Bond Activation by a Cationic Germylyne Complex

“…In this system, it is suggested that Lewis acidity of the Ge center facilitates the formyl C–H bond cleavage of an aldehyde on W and a base-stabilized metallogermylene forms as a key state, which undergoes hydrogermylation of another aldehyde to afford B . The mechanism is supported by Xie group’s calculations (DFT) with slight modification . This unique reaction encouraged us to investigate further reactivities of various substrates.…”

“…The 13 C{ 1 H} NMR chemical shifts were referenced to the carbon of deuterated solvents (CD 2 Cl 2 : 53.8 ppm, o-DCB-d 4 : 127.2 ppm). 13 C{ 1 H} NMR spectra were assigned by use of 1 H− 13 C HSQC and HMBC experiments. The 11 B, 19 F{ 1 H}, 29 Si{ 1 H}, and 31 P{ 1 H} NMR chemical shifts were referenced to BF 3 •OEt 2 (0.0 ppm), C 6 H 5 CF 3 (63.7 ppm), SiMe 4 (0.0 ppm), and 85% H 3 PO 4 (0.0 ppm), respectively, as external standards.…”

“…The mechanism is supported by Xie group's calculations (DFT) with slight modification. 13 This unique reaction encouraged us to investigate further reactivities of various substrates. However, neutral complex A showed almost no reactivity toward less polar substrates such as alkenes, alkynes, and dihydrogen.…”

A Silylyne Tungsten Complex Having an Eind Group on Silicon: Its Dimer–Monomer Equilibrium and Cycloaddition Reactions with Carbodiimide and Diaryl Ketones

“…The first step is a [2 + 2] cycloaddition between 1 and the ketone that gives 6 . Then, coordination of another ketone to the Si center of 6 forms a and o -C–H bond activation on the unsaturated W center in a occurs to give the metallosilylene b . A subsequent 1,4-H shift from W to the carbonyl carbon to give c followed by aryl migration from W to the carbonyl carbon of the second ketone forms the W–Si–O three-membered-ring intermediate d .…”

Enantioselective Total Synthesis of (+)‐Steenkrotin A and Determination of Its Absolute Configuration

“…A similar process for the interconversion of two diastereomers involving the reactiono fatungsten-germylyne complex with benzaldehyde has also been reported in our previous calculations. [34] …”