- Tertiary α-Silyl Alcohols by Diastereoselective Coupling of 1,3-Dienes and Acylsilanes Initiated by Enantioselective Copper-Catalyzed Borylation
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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.
- Feng, Jian-Jun,Oestreich, Martin
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p. 8211 - 8215
(2019/05/27)
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- Enantioselective Synthesis of Chiral 3-Substituted-3-silylpropionic Esters via Rhodium/Bisphosphine-Thiourea-Catalyzed Asymmetric Hydrogenation
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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.).
- Zhang, Zongpeng,Han, Zhengyu,Gu, Guoxian,Dong, Xiu-Qin,Zhang, Xumu
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p. 2585 - 2589
(2017/08/16)
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- Synthesis of Optically Pure Arylsilylcarbinols and Their Use as Chiral Auxiliaries in Oxacarbenium Ion Reactions
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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.
- Huckins, John R.,Rychnovsky, Scott D.
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p. 10135 - 10145
(2007/10/03)
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