21 research outputs found
Enantioconvergent Cross‐Couplings of Alkyl Electrophiles: The Catalytic Asymmetric Synthesis of Organosilanes
No full textEnantioconvergent Cross‐Couplings of Alkyl Electrophiles: The Catalytic Asymmetric Synthesis of Organosilanes
No full textChemInform Abstract: Efficient Synthesis of Bicyclo[6.3.0]undecadienones by Nazarov Cyclization/Regioselective Elimination.
No full textCorrection to “Enantioconvergent Alkylations of Amines by Alkyl Electrophiles: Copper-Catalyzed Nucleophilic Substitutions of Racemic α-Halolactams by Indoles”
No full textEnantioconvergent Alkylations of Amines by Alkyl Electrophiles: Copper-Catalyzed Nucleophilic Substitutions of Racemic α-Halolactams by Indoles
No full textTransition-metal catalysis has the potential to address shortcomings in the classic S_N2 reaction of an amine with an alkyl electrophile, both with respect to reactivity and to enantioselectivity. In this study, we describe the development of a user-friendly method (reaction at room temperature, with commercially available catalyst components) for the enantioconvergent nucleophilic substitution of racemic secondary alkyl halides (α-iodolactams) by indoles. Mechanistic studies are consistent with the formation of a copper(I)–indolyl complex that reacts at different rates with the two enantiomers of the electrophile, which interconvert under the reaction conditions (dynamic kinetic resolution). This investigation complements earlier work on photoinduced enantioconvergent N-alkylation, supporting the premise that this important challenge can be addressed by a range of strategies
Copper-Catalyzed Alkylation of Aliphatic Amines Induced by Visible Light
No full textAlthough the alkylation of an amine by an alkyl halide serves as a “textbook example” of a nucleophilic substitution reaction, the selective mono-alkylation of aliphatic amines by unactivated, hindered halides persists as a largely unsolved challenge in organic synthesis. We report herein that primary aliphatic amines can be cleanly mono-alkylated by unactivated secondary alkyl iodides in the presence of visible light and a copper catalyst. The method operates under mild conditions (–10 °C), displays good functional-group compatibility, and employs commercially available catalyst components. A trapping experiment with TEMPO is consistent with C–N bond formation via an alkyl radical in an out-of-cage process
Enantioconvergent Alkylations of Amines by Alkyl Electrophiles: Copper-Catalyzed Nucleophilic Substitutions of Racemic α‑Halolactams by Indoles
No full textTransition-metal
catalysis has the potential to address shortcomings
in the classic SN2 reaction of an amine with an alkyl electrophile,
both with respect to reactivity and to enantioselectivity. In this
study, we describe the development of a user-friendly method (reaction
at room temperature, with commercially available catalyst components)
for the enantioconvergent nucleophilic substitution of racemic secondary
alkyl halides (α-iodolactams) by indoles. Mechanistic studies
are consistent with the formation of a copper(I)–indolyl complex
that reacts at different rates with the two enantiomers of the electrophile,
which interconvert under the reaction conditions (dynamic kinetic
resolution). This investigation complements earlier work on photoinduced enantioconvergent N-alkylation, supporting
the premise that this important challenge can be addressed by a range
of strategies
A Stochastic Simulation Framework for the Government of Canada's Debt Strategy
No full textDebt strategy is defined as the manner in which a government finances an excess of government expenditures over revenues and any maturing debt issued in previous periods. The author gives a thorough qualitative description of the complexities of debt strategy analysis and then demonstrates that it is, in fact, a problem in stochastic optimal control. Although this formal definition is conceptually useful, the author recommends the use of simulation to help characterize the set of strategies that a government can use to fund its borrowing requirements. He then describes in detail a stochastic simulation framework, building from previous work in Bolder (2001, 2002); this framework forms one important element in the debt strategy decision-making process employed by the Government of Canada. The primary objective in constructing this stochastic simulation framework is to learn about the nature of the risk and cost trade-offs associated with different financing strategies. To this end, the paper includes a detailed description of the model; a set of possible debt cost and risk measures, including one potentially useful conditional risk measure; illustrative results under normal stochastic conditions; an analysis of the sensitivity of the results to various key model parameters; a novel approach to stress testing; and a possible framework for selecting a financing strategy, given assumptions about government risk preferences.Debt management; Econometric and statistical methods; Economic models
ChemInform Abstract: Asymmetric Copper‐Catalyzed C—N Cross‐Couplings Induced by Visible Light.
No full text
