- Copper-Catalyzed Asymmetric Hydroallylation of Vinylsilanes
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A copper-catalyzed asymmetric hydroallylation of readily available vinylsilanes with allylic phosphates in the presence of hydrosilane was developed. These transformations can be performed under mild reaction conditions and provide the useful chiral organ
- Guo, Xiaobing,Niu, Junbo,Wang, Simin,Xiong, Tao,Zhang, Qian,Zhang, Qiao
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supporting information
(2022/02/21)
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- Active-releasing cyclic siloxanes
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Cyclic siloxanes that contain releasable active ingredients are described. The active ingredient can be an alcohol or enolizable carbonyl-containing compound such as a ketone, aldehyde, or ester. The product siloxanes are useful in a variety of personal and household care products where slow or controlled release of active ingredient is desired. A preferred embodiment utilizes substituents that when released as active ingredients are fragrant.
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Page/Page column 3
(2008/06/13)
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- Fragrance releasing olefinic silanes
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Fragrant silanes having the formula:(R1O)a(R2O)b(R3O)c(R4)d(R5)eSiR6where R1, R2 and R3 are derived from the group of alcohols consisting of R1OH, R2OH and R3OH wherein R1OH, R2OH and R3OH are fragrant alcohols or alternatively R1, R2 and R3 are derived f
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- Hydrogen/deuterium exchange reactions and transfer hydrogenations catalyzed by [C5Me5Rh(olefin)2] complexes: Conversion of alkoxysilanes to silyl enolates
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A series of [C5Me5Rh(CH2=CHR)2] complexes (1a-e) have been prepared in which the olefin bears a bulky silyl substituent, R = (a) SiMe3, (b) SiMe2OEt, (c) Si(OiPr)3, (d) SiMe(OSiMe3)2, (e) SiPh2Oi-Pr. The solid-state structure of 1c has been determined by X-ray crystallography. When complex 1a is heated (50°C) in deuterated solvents (C6D6, C6D5CD3, C6D5Cl, or (CD3)2CO), deuterium is incorporated into the olefinic sites. Thermolysis at higher temperatures results in further H/D exchange and deuteration of both the SiMe3 and C5Me5 groups. Heating 1a in C6D6 with added substrates (aniline, MeOtBu, MeOSiMe3, Cp2Fe, cyclopentene, or EtOAc) results in deuteration of these substrates via shuttling of deuterium from C6D6 to the olefinic sites and then into certain sites of the substrates. Thermolysis of 1a in the presence of vinyltrimethylsilane at higher temperatures results in C-Si bond cleavage and generation of a silacyclopentadiene complex (6) whose structure was determined by X-ray analysis. Thermolysis of 1c in C6D6 results in facile H/D exchange and incorporation of deuterium not only into the vinylic positions but also into the methine and methyl groups of the isopropyl substituents. At 90°C in the presence of CH2=CHSi(OiPr)3 a catalytic transfer hydrogenation is observed which converts the vinylsilane to the silyl enolate, Et(iPrO)2SiOCMe=CH2. A series of catalytic transfer hydrogenations were carried out in which alkoxysilanes CH2=CHSiMe2OR (R = Et, n-Bu, CHMeEt, C2H4tBu, C2H4Ph, CHMePh, CHMeCH2Ph) were converted to the corresponding silyl enolates. Catalytic conversion of the vinylaminosilane CH2=CHSiMe2NHC2H4Ph to the silyl enamine EtSiMe2NHC2H2Ph is also reported.
- Lenges, Christian P.,White, Peter S.,Brookhart, Maurice
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p. 4385 - 4396
(2007/10/03)
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