Chemoselective deoxygenation of ether-substituted alcohols and carbonyl compounds by B(C6F5)3-catalyzed reduction with (HMe2SiCH2)2
B(C6F5)3-catalyzed deoxygenation of ether-substituted alcohols and carbonyl compounds has been developed using (HMe2SiCH2)2 as the reductant. This unique reagent shows distinct superiority over traditional one silicon-centered hydrosilanes, giving the corresponding alkanes in high yields with good tolerance of ethers, aryl halides and alkenes. The control experiments suggest that (HMe2SiCH2)2 might facilitate the approach in an intramolecular Si/O activation manner.
Yang, Wenyu,Gao, Lu,Lu, Ji,Song, Zhenlei
supporting information
p. 4834 - 4837
(2018/05/23)
(HMe 2 SiCH 2) 2: A Useful Reagent for B(C 6 F 5) 3 -Catalyzed Reduction-Lactonization of Keto Acids: Concise Syntheses of (-)- cis -Whisky and (-)- cis -Cognac Lactones
(HMe 2 SiCH 2) 2 has been utilized as a useful reagent for B(C 6 F 5) 3 -catalyzed reduction-lactonization of keto acids to synthesize γ- and δ-lactones. The process led concisely to (-)- cis -whisky and (-)- cis -cognac lactones in respective overall yields of 32% and 36%.
Selective catalytic monoreduction of dichlorooligosilanes with Grignard reagents
Transition metal-catalyzed monoreduction of dichlorooligosilanes with Grignard reagents is reported. Among the examined catalysts, group 4 metal chlorides such as TiCl4 and Cp2TiCl2 gave the highest reactivity and good selectivity. The reducing power is effectively controlled by changing the catalysts and Grignard reagents to achieve sufficient selectivity depending on the oligosilane substrates.
Hydrosilanes are not always reducing agents for carbonyl compounds but can also induce dehydration: A ruthenium-catalyzed conversion of primary amides to nitriles
A practical procedure for production of nitriles is offered by the triruthenium carbonyl cluster catalyzed dehydration of primary carboxamides with hydrosilanes under neutral conditions. This is the first example that a transition-metal-catalyzed activation of Si-H bonds does not lead to the reduction of carbonyl compounds but to dehydration. Possible mechanisms for the dehydration is discussed on the basis of NMR spectroscopic detection of intermediary species. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
Chloroplatinic acid catalyzed cyclization of silanes bearing pendant acetylenic groups
Chloroplatinic acid catalyzed, intramolecular hydrosilylation of acetylenes of structure HMe2SinSiMe2CCR (R = H or Ph, n = 2 or 3) proceeds via syn addition of the Si-H group to the carbon triple bond to give, predominantly, cyclic products having an
Steinmetz, Mark G.,Udayakumar, B. S.
p. 1 - 16
(2007/10/02)
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