Samarium(II)-induced ring-expansion reaction of 1,2-cyclobutanedicarboxylates to produce cyclopentanones
摘要:
Novel ring-expansion reaction of 1,2-cyclobutanedicarboxylates with Sm(II) in the presence of HMPA with a catalytic amount of methanol was found to provide 2-oxocyclopentanecarboxylates. (C) 2003 Elsevier Ltd. All rights reserved.
Photosensitised regioselective [2+2]-cycloaddition of cinnamates and related alkenes
作者:Santosh K. Pagire、Asik Hossain、Lukas Traub、Sabine Kerres、Oliver Reiser
DOI:10.1039/c7cc06710k
日期:——
An efficient method for the synthesis of substituted cyclobutanes from cinnamates, chalcones, and styrenes has been developed utilizing a visible-light triplet sensitisation mode. This reaction provides a diverse range of substituted cyclobutanes in high yields under mild conditions without the need of external additives. Good regioselectivity is obtained due to strong π–π-stacking of arene moieties
Using non-covalent interactions to direct regioselective 2+2 photocycloaddition within a macrocyclic cavitand
作者:Nga Nguyen、Aspen Rae Clements、Mahesh Pattabiraman
DOI:10.1039/c5nj02376a
日期:——
completely from a head-to-head dimer to a head-to-tail dimer. The reactions were also stereoselective in most cases. Stoichiometry experiments were performed to explore relative stabilities of the complexes, which indicate that the ternary complex is more stable than others. Selectivity in the photocycloaddition reaction was also applied retrospectively to deduce intermolecular orientations. Time-dependent
Hydrogen Atom Transfer Reactions via Photoredox Catalyzed Chlorine Atom Generation
作者:Samantha Rohe、Avery O. Morris、Terry McCallum、Louis Barriault
DOI:10.1002/anie.201810187
日期:2018.11.26
waste‐limiting, and atom‐economical. The catalytic generation of chlorineatoms from chloride ions is one of the most challenging redox processes, where the requirement of harsh and oxidizing reaction conditions renders it seldom utilized in synthetic applications. We report the mild, controlled, and catalytic generation of chlorineatoms as a new opportunity for access to a wide variety of hydrogen atom transfer
which are building blocks for a variety of biologically active molecules and natural products. However, most attempts at the above [2+2] addition have focused on solid‐state, molten‐state, or host–guest systems under ultraviolet‐lightirradiation in order to overcome the competition of facile geometric isomerization of nonrigid olefins. We report a general and simple method to realize the intermolecular
Templating Photodimerization of <i>trans</i>-Cinnamic Acid Esters with a Water-Soluble Pd Nanocage
作者:S. Karthikeyan、V. Ramamurthy
DOI:10.1021/jo0617722
日期:2007.1.1
trans-cinnamic acid methyl esters in water. Irradiation of the host−guest complexes of trans-cinnamic acid methyl esters with the Pd nanocage resulted in selective formation of a syn head−head dimer in addition to the corresponding cis isomer. These results suggest that the guest molecules are preoriented in a selective fashion with the hydrophilic ester group facing water and the hydrophobic aryl group