1515-81-7Relevant articles and documents
Physical organic chemistry of transition metal carbene complexes. 24. Thermodynamic and kinetic acidities of phenyl-substituted (benzylmethoxycarbene)pentacarbonylchromium(0) complexes. Is there a transition-state imbalance?
Bernasconi, Claude F.,Sun, Weitao
, p. 2299 - 2304 (2002)
A kinetic study of the reversible deprotonation of phenyl-substituted (benzylmethoxycarbene)pentacarbonylchromium(0) complexes by OH- and by a series of primary aliphatic and a series of secondary alicyclic amines in 50% MeCN-50% water (v/v) at 25°C is reported. Bronsted αCH values (dependence on carbene complex acidity) and βB values (dependence on amine basicity) were determined. According to current notions about proton transfers involving carbon acids activated by φ-acceptors, αCH was expected to substantially exceed βB, the result of transition-state imbalances that are characteristic of such reactions. However we find that αCH and βB have essentially the same values, which are close to0.5. It is shown that these findings do not indicate the absence of an imbalance but rather suggest that the manifestation of the imbalance is masked by the φ-donor effect (3H-Z ? 3H-Z±) of the methoxy group.
Site-Selective Alkoxylation of Benzylic C?H Bonds by Photoredox Catalysis
Lee, Byung Joo,DeGlopper, Kimberly S.,Yoon, Tehshik P.
supporting information, p. 197 - 202 (2019/11/26)
Methods that enable the direct C?H alkoxylation of complex organic molecules are significantly underdeveloped, particularly in comparison to analogous strategies for C?N and C?C bond formation. In particular, almost all methods for the incorporation of alcohols by C?H oxidation require the use of the alcohol component as a solvent or co-solvent. This condition limits the practical scope of these reactions to simple, inexpensive alcohols. Reported here is a photocatalytic protocol for the functionalization of benzylic C?H bonds with a wide range of oxygen nucleophiles. This strategy merges the photoredox activation of arenes with copper(II)-mediated oxidation of the resulting benzylic radicals, which enables the introduction of benzylic C?O bonds with high site selectivity, chemoselectivity, and functional-group tolerance using only two equivalents of the alcohol coupling partner. This method enables the late-stage introduction of complex alkoxy groups into bioactive molecules, providing a practical new tool with potential applications in synthesis and medicinal chemistry.
Methoxymethylation and benzyloxymethylation of aryl bromides
Panda, Biswajit
, p. 981 - 985 (2020/06/26)
The methoxymethylation and benzyloxymethylation of aryl bromides methodology was reported here. The transition metal free, high yielding one pot procedure will be useful for synthetic community.
