The Trepobatinae (Gerridae) of New Guinea and surrounding regions, with a review of the world fauna. Part 6. Phylogeny, biogeography, world checklist, bibliography and final taxonomic addenda
SuperQuat 5,5-dimethyl-4-iso-propyloxazolidin-2-one as a mimic of Evans 4-tert-butyloxazolidin-2-one
作者:Steven D. Bull、Stephen G. Davies、A. Christopher Garner、Dennis Kruchinin、Min-Suk Key、Paul M. Roberts、Edward D. Savory、Andrew D. Smith、James E. Thomson
DOI:10.1039/b605244d
日期:——
The incorporation of a gem-dimethyl group at the 5-position of a chiral oxazolidinone biases the conformation of the adjacent C(4)-stereodirecting group such that the gem-dimethyl-4-iso-propyl combination mimics a C(4)-tert-butyl group, providing higher levels of stereocontrol than a simple 4-iso-propyloxazolidinone. The generality of this principle is demonstrated with applications in stereoselective enolate alkylations, kinetic resolutions, Diels–Alder cycloadditions and Pd-catalysed asymmetric acetalisation reactions.
Catalytic conversion of ketones to esters <i>via</i> C(O)–C bond cleavage under transition-metal free conditions
作者:Murugan Subaramanian、Palmurukan M. Ramar、Jagannath Rana、Virendra Kumar Gupta、Ekambaram Balaraman
DOI:10.1039/d0cc03312j
日期:——
The catalytic conversion of ketones to esters via C(O)–C bond cleavage under transition-metal free conditions is reported. This catalytic process proceeds under solvent-free conditions and offers an easy operational procedure, broad substrate scope with excellent selectivity, and reaction scalability.
Size‐Induced Inversion of Selectivity in the Acylation of 1,2‐Diols
作者:Stefanie Mayr、Hendrik Zipse
DOI:10.1002/chem.202101905
日期:2021.12.23
Lewis-base catalyzed acylation of aromatic 1,2-ethylenediols with anhydrides depends strongly on the size of the reagents and the π-system of the diol. Steric effects have a larger impact on reactions of primary hydroxyl groups in the 1,2-diol as well as the monoester than those of secondary hydroxyl groups. For sterically demanding anhydrides this flips the selectivity towards secondaryalcohols.
Synthesis of Acyclic Ketones by Catalytic, Bidirectional Homologation of Formaldehyde with Nonstabilized Diazoalkanes. Application of a Chiral Diazomethyl(pyrrolidine) in Total Syntheses of Erythroxylon Alkaloids
作者:Andrew J. Wommack、Jason S. Kingsbury
DOI:10.1021/jo401377a
日期:2013.11.1
This work offers a catalytic approach to convergent ketone assembly based upon formal and tandem C–H insertion of diazoalkanes in the presence of limiting amounts of monomeric formaldehyde, which is easily generated as a gas by thermolysis of the inexpensive and abundant paraformaldehyde (∼30 USD/kg). The method forms di-, tri-, and even tetrasubstituted acetones with high efficiency, and it has streamlined
Solubilizing agents for active or functional organic compounds
申请人:Bertz H. Steven
公开号:US20050152858A1
公开(公告)日:2005-07-14
An active or functional organic compound is solubilized in a diaryl organic compound having a polar or polarizable functional group therein, as a solvent, cosolvent or additive, to form a composition thereof. Representative active or functional organic compounds include those present in personal care products, e.g., sunscreens containing UVA/UVB absorbing compounds, such as avobenzone, benzophenone-3, and 4-methylbenzylidene camphor. Such compositions also show increased SPF, UVA/UVB absorbance ratio, and critical wavelength performance properties.