18666-54-1Relevant academic research and scientific papers
Visible-Light-Induced Catalyst-Free Carboxylation of Acylsilanes with Carbon Dioxide
Fan, Zhengning,Yi, Yaping,Chen, Shenhao,Xi, Chanjuan
, p. 2303 - 2307 (2021/04/05)
Intermolecular carbon-carbon bond formation between acylsilanes and carbon dioxide (CO2) was achieved by photoirradiation under catalyst-free conditions. In this reaction, siloxycarbenes generated by photoisomerization of the acylsilanes added to the C═O bond of CO2 to give α-ketocarboxylates, which underwent hydrolysis to afford α-ketocarboxylic derivatives in good yields. Control experiments suggest that the generated siloxycarbene is likely to be from the singlet state (S1) of the acylsilane and the addition to CO2 is not in a concerted manner.
Tertiary α-Silyl Alcohols by Diastereoselective Coupling of 1,3-Dienes and Acylsilanes Initiated by Enantioselective Copper-Catalyzed Borylation
Feng, Jian-Jun,Oestreich, Martin
, p. 8211 - 8215 (2019/05/27)
An efficient synthesis of functionalized tertiary α-silyl alcohols by an enantio- and diastereoselective copper-catalyzed three-component coupling of 1,3-dienes, bis(pinacolato)diboron, and acylsilanes is reported. The reaction proceeds well with different 1,3-dienes and a broad range of aryl- as well as alkenyl- but also alkyl-substituted acylsilanes. The target compounds are formed with high regio-, diastereo-, and enantioselectivity (up to 99 % ee and d.r. >20:1) and are highly versatile synthetic building blocks.
Enantioselective Synthesis of Chiral 3-Substituted-3-silylpropionic Esters via Rhodium/Bisphosphine-Thiourea-Catalyzed Asymmetric Hydrogenation
Zhang, Zongpeng,Han, Zhengyu,Gu, Guoxian,Dong, Xiu-Qin,Zhang, Xumu
, p. 2585 - 2589 (2017/08/16)
We have successfully developed the asymmetric hydrogenation of β-silyl-α,β-unsaturated esters to prepare chiral 3-substituted-3-silylpropionic ester products catalyzed by rhodium/bisphosphine-thiourea (ZhaoPhos) with excellent results (up to 97% yield, >99% ee, 1500 TON). Moreover, our hydrogenation products can be efficiently converted to other important organic molecules, such as chiral ethyl (R)-3-hydroxy-3-phenylpropanoate or (R)-3-[dimethyl(phenyl)silyl]-3-phenylpropanoic acid. (Figure presented.).
Catalytic asymmetric alkylation of acylsilanes
Rong, Jiawei,Oost, Rik,Desmarchelier, Alaric,Minnaard, Adriaan J.,Harutyunyan, Syuzanna R.
, p. 3038 - 3042 (2015/04/14)
The highly enantioselective addition of Grignard reagents to acylsilanes is catalyzed by copper diphosphine complexes. This transformation affords α-silylated tertiary alcohols in up to 97% yield and 98:2 enantiomeric ratio. The competing Meerwein-Ponndorf-Verley reduction is suppressed by the use of a mixture of Lewis acid additives. The chiral catalyst can be recovered as a copper complex and used repeatedly without any loss of catalytic activity.
Enantioselective synthesis of α-silylamines by meerwein-ponndorf- verley-type reduction of α-silylimines by a chiral lithium amide
Kondo, Yasuhiro,Sasaki, Michiko,Kawahata, Masatoshi,Yamaguchi, Kentaro,Takeda, Kei
, p. 3601 - 3609 (2014/05/06)
Meerwein-Ponndorf-Verley-type reduction of N-tosylsilylimines with chiral lithium amide 2 affords α-silylamines in high enantioselectivity. Since the enantioselectivity observed was inconsistent with our previously proposed chairlike six-membered transition structure, we performed density functional theory (DFT) calculations on transition states leading to (S)- and (R)-7a and (S)- and (R)-7e using an N-phenylsulfonyl derivatives 12 and 13 as model systems. Results of the calculations showed that the structures are considerably deformed from the chairlike form with steric repulsions between the 1′-methylene group and the imine-carbon substituents playing an important role in the control of the enantioselectivity.
Oxidation of gem-borylsilylalkylcoppers to acylsilanes with air
Kondo, Junichi,Shinokubo, Hiroshi,Oshima, Koichiro
, p. 1185 - 1187 (2007/10/03)
1-Boryl-1-silylalkylcoppers react with molecular oxygen in the presence of pyridine to afford acylsilanes efficiently. The one-pot process consists of two reactions: alkylation of 1-boryl-1-chloro-silylmethyllithium with Grignard reagents in the presence of copper(I) cyanide and aerobic oxidation of the alkylcopper species. This procedure enables us to access the divergent synthesis of acylsilanes.
Preparation of α-silyl- or α,α-bis(silyl)-substituted alkylcopper reagents and their synthetic use
Kondo, Junichi,Inoue, Atsushi,Ito, Yuki,Shinokubo, Hiroshi,Oshima, Koichiro
, p. 3361 - 3369 (2007/10/03)
Treatment of chlorobis(methyldiphenylsilyl)methyllithium with various alkyl and aryl Grignard reagents and CuCN·2LiCl afforded 1,1- disilylalkylcopper species. The aerobic oxidation of the resulting copper reagents provided a variety of acylsilanes in good yields. Meanwhile, treatment of dichloro(methyldiphenylsilyl)methyllithum with Bu2CuLi·LiCN provided 1-cyano-1-silylalkylcopper species via consecutive double 1,2-migration of alkyl and cyano groups.
Synthesis of Optically Pure Arylsilylcarbinols and Their Use as Chiral Auxiliaries in Oxacarbenium Ion Reactions
Huckins, John R.,Rychnovsky, Scott D.
, p. 10135 - 10145 (2007/10/03)
A family of arylsilylcarbinols was synthesized and investigated as chiral auxiliaries for oxacarbenium ion reactions. The optically pure arylsilylcarbinols were prepared using Noyori's transfer hydrogenation catalyst 11. The transfer hydrogenation shows very good enantioselectivities and turnover efficiency for the aryl silyl ketones and is the method of choice for preparing these optically pure alcohols. The diastereoselective addition of allyltrimethylsilane to an in situ generated oxacarbenium ion was explored using Marko's conditions. The selectivity for a representative aliphatic aldehyde was very good, but the selectivity was significantly reduced with unsaturated and aromatic aldehydes. The range of selectivities with different auxiliaries was narrow, and the most practical auxiliary is the phenylsilylcarbinol 2.
Efficient formation and cleavage of disilanes by potassium-graphite. Silylation with silyl metal reagents
Fuerstner, Alois,Weidmann, Hans
, p. 15 - 22 (2007/10/02)
Potassium-graphite laminate (C8K) very rapidly forms disilanes from chlorosilanes and then rapidly cleaves the disilanes to give silyl potassium reagents which can be converted into potassium silyl cuprates, -manganates, and -vanadates that are useful for various nucleophilic substitution and addition reactions.
