Regioselective Hydrosilylation of Olefins Catalyzed by a Molecular Calcium Hydride Cation
作者:Danny Schuhknecht、Thomas P. Spaniol、Laurent Maron、Jun Okuda
DOI:10.1002/anie.201909585
日期:2020.1.2
Chemo- and regioselectivity are often difficult to control during olefin hydrosilylation catalyzed by d- and f-block metal complexes. The cationichydride of calcium [CaH]+ stabilized by an NNNNmacrocycle was found to catalyze the regioselective hydrosilylation of aliphatic olefins to give anti-Markovnikov products, while aryl-substituted olefins were hydrosilyated with Markovnikov regioselectivity
Monohydrosilanes can be prepared selectively in high yields from the reaction of various aryl and alkyl iodides with ytterbium metal followed by the reaction with dihydrosilanes.
Alkyl iodides and tertiary silanes were successfully coupled with good functional group tolerance using a Pt(P(tBu)3)2/(iPr)2EtN/CH3CN system. The utility of the methodology is demonstrated by the synthesis of silafluofen, a Si-containing insecticide.
Regioselective and stereoselective synthesis of trisubstituted alkenyl silanes via hydrosilylation is challenging. Herein, we report the first β-anti-selective addition of silanes to thioalkynes with B(C6F5)3 as the catalyst. The reaction shows broad substrate scope. The products were proven to be useful intermediates to other trisubstituted alkenyl silanes by Ni-catalyzed stereoretentive cross-coupling reactions
[EN] METHOD OF PREPARING SILANOLS WITH SELECTIVE CYTOCHROME P450 VARIANTS AND RELATED COMPOUNDS AND COMPOSITIONS<br/>[FR] PROCÉDÉ DE PRÉPARATION DE SILANOLS AVEC DES VARIANTS SÉLECTIFS DU CYTOCHROME P450 ET COMPOSÉS ET COMPOSITIONS ASSOCIÉS
申请人:DOW SILICONES CORP
公开号:WO2021168228A1
公开(公告)日:2021-08-26
This disclosure provides a method of preparing a silanol-functional organosilicon compound with a cytochrome P450 variant that facilitates the oxidization of a silyl hydride group to a silanol group in the presence of oxygen. The method includes combining the cytochrome P450 variant and an organosilicon compound having at least one silicon-bonded hydrogen atom to give a reaction mixture and exposing the reaction mixture to oxygen to oxidize the organosilicon compound, thereby preparing the silanol-functional organosilicon compound. Cytochrome P450 variants suitable for use in the method are also disclosed, along with methods for engineering and optimizing the same. Nucleic acids encoding the cytochrome P450 variants and compositions, expression vectors, and host cells including the same are also disclosed.