排序方式: 共有17条查询结果,搜索用时 328 毫秒
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Under hydrogen autotransfer conditions employing a catalyst derived from [Ir(cod)Cl]2 and BIPHEP, 1,3-cyclohexadiene (CHD) couples to benzylic alcohols 1a-9a to furnish carbonyl addition products 1c-9c, which appear as single diastereomers with variable quantities of regioisomeric adducts 1d-9d. Under related transfer hydrogenation conditions employing isopropanol as terminal reductant, identical carbonyl adducts 1c-9c are obtained from the aldehyde oxidation level. Isotopic labeling studies corroborate a mechanism involving hydrogen donation from the reactant alcohol or sacrificial alcohol (i-PrOH). 相似文献
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Patman RL Williams VM Bower JF Krische MJ 《Angewandte Chemie (International ed. in English)》2008,47(28):5220-5223
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JohnF. Bower InSu Kim RyanL. Patman MichaelJ. Krische 《Angewandte Chemie (International ed. in English)》2009,48(1):34-46
Classical protocols for carbonyl allylation, propargylation and vinylation typically rely upon the use of preformed allyl metal, allenyl metal and vinyl metal reagents, respectively, mandating stoichiometric generation of metallic byproducts. Through transfer hydrogenative C C coupling, however, carbonyl addition may be achieved from the aldehyde or alcohol oxidation level in the absence of stoichiometric organometallic reagents or metallic reductants. Here, we review transfer hydrogenative methods for carbonyl addition, which encompass the first catalytic protocols enabling direct C H functionalization of alcohols. 相似文献
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The functional Ito formula, in the form df() = f( + d ) f(),is formulated and proved in the context of a Lie algebra L associatedwith a quantum (non-commutative) stochastic calculus. Here fis an element of the universal enveloping algebra U of L, andf() + d() f() is given a meaning using the coproductstructure of U even though the individual terms of this expressionhave no meaning. The Ito formula is equivalent to a chaoticexpansion formula for f() which is found explicitly. 1991 MathematicsSubject Classification: primary 81S25; secondary 60H05; tertiary18B25. 相似文献
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Leung JC Patman RL Sam B Krische MJ 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(44):12437-12443
Nonsymmetric 1,2-disubstituted alkynes engage in reductive coupling to a variety of aldehydes under the conditions of ruthenium-catalyzed transfer hydrogenation by employing formic acid as the terminal reductant and delivering the products of carbonyl vinylation with good to excellent levels of regioselectivity and with complete control of olefin stereochemistry. As revealed in an assessment of the ruthenium counterion, iodide plays an essential role in directing the regioselectivity of C-C bond formation. Isotopic labeling studies corroborate reversible catalytic propargyl C-H oxidative addition in advance of the C-C coupling, and demonstrate that the C-C coupling products do not experience reversible dehydrogenation by way of enone intermediates. This transfer hydrogenation protocol enables carbonyl vinylation in the absence of stoichiometric metallic reagents. 相似文献