Organosilane Synthessis
Our Goal
Our objective is to synthesize alkyl organosilanes by cross-coupling reactions and utilize them as alkyl synthons, again employing cross-coupling reactions.
Switch between the concerted and MHAT pathways
We have developed a hydroalkylation for toggling between the concerted and MHAT pathways through a ligand modulation, yielding a very efficient regiodivergent synthesis of alkyl−Si(OEt)3 with sensitive functional groups and α-quaternary silicon.
Anti-Selective Carbosilylation
we developed a highly efficient anti-selective carbosilylation for the synthesis of stereodefined and highly substituted vinylsilanes. Silylzinc reagents are highly functional group tolerant, and their applications in cross-coupling reactions are hampered by their synthesis from pyrophoric silyllithium and dissolved lithium salts. Our novel solid silylzinc reagents that overcome these limitations are employed in the exclusive synthesis of Z-vinylsilanes via the antiselective addition of TMSZnI to terminal alkynes and the subsequent cross-coupling with activated alkyl halides.
Synthesis of α-Vinyltrialkoxysilanes
Hydrosilylation of alkynes inevitably yields α- and β-isomers of vinyltrialkoxysilanes even with complex ligands and catalysts, limiting its usage in organic synthesis. We report the synthesis of α-vinyltrialkoxysilanes via cross-electrophile C(sp2)–C(sp2) coupling of bromoalkenes.
Enantiospecific silylation
we developed nickel-mediated enantiospecific silylation via C(sp3)−O bond cleavage for the first time.
cross-coupling reaction of carbamates with silylmagnesium reagents
The C-O bonds are kinetically inert in cross-coupling reactions compared to those of carbon–halogen bonds. We disclosed an unprecedented nickel mediated cross-coupling of carbamates with silylmagnesium reagents that does not require the expensive silylboranes.
Solid Silylzinc reagents
We developed novel silylzinc reagents for the first time. The direct synthesis of PhMe2SiZnI and Me3SiZnI reagents by employing a coordinating TMEDA ligand was achieved. We have also obtained single crystal XRD structures. Importantly, they can be obtained as solids and stored for longer periods at 4 C. Silylzinc reagentsare notoriously difficult to synthesize because they are obtained by a pyrophoric reaction of silyllithium, particularly M33SiLi which is itself prepared by the reaction of MeLi and disilane. Furthermore, the dissolved LiCl in silylzinc may have a detrimental effect. A synthetic method that can avoid silyllithium and involves a direct synthesis of silylzinc reagents from silyl halides is arguably the simplest and most economical strategy.
Synthesis of acylsilanes
For the first time, we have developed a method for direct synthesis of silylzinc reagents from silyl iodides and their structures were confirmed by single-crystal XRD. Unlike the use of pyrophoric silyllithium in the synthesis of silylzinc reagents, the current method offers a simplified direct method to access them from silyl halides. The absence of dissolved lithium/magnesium salts in these reagents could be beneficial for various chemical processes. We have also demonstrated the practical synthesis of acylsilanes from unactivated alkyl acid chlorides by nickel, copper and dual catalysis.
To study the general applicability of this new solid Me3SiZnI, we performed a wide range of organic transformations. Both branched and linear allylsilanes were synthesized through allylation.
The copper-mediated 1,4-addition of Me3SiZnI and PhMe2SiZnI with enones and yielded the β-silyl ketones. We also employed PhMe2SiZnI in a novel Brook-rearrangement/cross-coupling of benzaldehyde and bromoarene.
we have demonstrated the efficacy of the novel solid trimethylsilyl zinc reagent in the synthesis of aryl and alkyl trimethylsilanes.
