Catalytic Reduction of Cyclic Ethers with Hydrosilanes

Abstract

Catalytic reductive transformations of ethers as a synthetic building block are an important class of chemical reactions because a range of essential chemical feedstocks and fuels in contemporary life can be prepared through the key step of ethereal C−O bond cleavage of cellulosic biomass. Although conventional stoichiometric and catalytic methods for sp2‐ and sp3‐C−O bond cleavage of linear ethers and alcohols with hydrosilanes are well established, silylative ring opening of cyclic ethers has been less highlighted in this context. This review outlines catalytic systems for the silylative reduction of a range of cyclic ethers, including epoxides and sugars, leading to the corresponding alcohols and/or hydrocarbons. The chemical reactivity and selectivity of these ring‐opening catalytic processes are discussed with respect to the type of substrates; the representative catalytic working modes are also described.

Cobalt-catalysed hydroformylation of epoxides in the presence of phosphine oxides

“…As an example, silylformylation, which allows in situ protection of the alcohol group to give β-silyloxyaldehydes, have been performed. [50][51][52] The strategies to protect the formyl group involve, for example, its acetalization. Nozaki and co-workers described the synthesis of β-hydroxy dimethyl acetals from epoxides by Co 2 (CO) 8 -catalysed tandem hydroformylation/acetalization performed in the presence of an excess of trimethyl orthoformate.…”

Polymethylhydrosiloxane (PMHS) as Sustainable Reductant in the Titanocene Catalyzed Epoxide Hydrosilylation

“…Catalytic epoxide hydrosilylations are attractive reactions for the preparation of alcohols if the regioselectivity of ring opening and the formal transfer of hydride proceed with high catalyst control. [1] In particular, reactions that formally lead to anti-Markovnikov alcohols are of potential practical importance. These hydrosilylations are important, because a two-step sequence for the anti-Markovnikov addition of water to olefins (Scheme 1) becomes available.…”

“…Catalytic epoxide hydrosilylations are attractive reactions for the preparation of alcohols if the regioselectivity of ring opening and the formal transfer of hydride proceed with high catalyst control [1] . In particular, reactions that formally lead to anti ‐Markovnikov alcohols are of potential practical importance.…”

B(C6F5)3-Catalyzed Dehydrocoupling of POSS Silanols with Hydrosilanes: A Metal-Free Strategy for Effecting Functionalization of Silsesquioxanes

“…On the other hand, tris­(pentafluorophenyl)­borane B­(C 6 F 5 ) 3 represents one of the strong Lewis acids and possesses catalytic activity in numerous processes; it also employs various organosilicon compounds. The applications of B­(C 6 F 5 ) 3 are extensive in diverse reactions in organic as well as organosilicon chemistry. , B­(C 6 F 5 ) 3 was found to be very effective at initiating olefin polymerization, , aldol-type Michael reactions, Diels–Alder reactions, borylation, hydrogenation, hydrosilylation, frustrated Lewis pair (FLP) chemistry, and other processes. − B­(C 6 F 5 ) 3 also promotes the silylation of alcohols and phenols with silanes − or the reduction of primary alcohols and ethers. , Furthermore, Rubinsztajn et al presented a wide range of the uses of B­(C 6 F 5 ) 3 in organosilicon and polymer chemistry. − …”

“…46−50 B(C 6 F 5 ) 3 also promotes the silylation of alcohols and phenols with silanes 51−53 or the reduction of primary alcohols and ethers. 54,55 Furthermore, Rubinsztajn et al presented a wide range of the uses of B(C 6 F 5 ) 3 in organosilicon and polymer chemistry. 56−59 However, despite the wide applications of B(C 6 F 5 ) 3 , we report herein the first and unprecedented one-pot procedure for the synthesis of silsesquioxane derivatives in the presence of B(C 6 F 5 ) 3 .…”