Catalyst-Controlled Wacker-Type Oxidation: Facile Access to Functionalized Aldehydes

The aldehyde-selective oxidation of alkenes bearing diverse oxygen groups in the allylic and homoallylic position was accomplished with a nitrite-modified Wacker oxidation. Readily available oxygenated alkenes were oxidized in up to 88% aldehyde yield and as high as 97% aldehyde selectivity. The aldehyde-selective oxidation enabled the rapid, enantioselective synthesis of an important pharmaceutical agent, atomoxetine. Finally, the influence of proximal functional groups on this anti-Markovnikov reaction was explored, providing important preliminary mechanistic insight

Progress Towards the Total Synthesis of a Stable (–)-Xestospongin C Derivative

The marine sponge alkaloids xestospongins and aruguspongines have well-established biological activities, including the inhibition of inositol trisphosphate receptors and the prevention of inositol trisphosphate mediated intracellular calcium release. These alkaloids are highly valuable in the study of the inositol trisphosphate and calcium signaling pathways in cells because few viable alternative inhibitors exist. However, xestospongin C – the most potent of these alkaloids – is not stable during storage. The goal of this study was to implement a thirteen-step synthesis of a xestospongin C derivative, designed to enhance storage stability and provide a reliable inhibitor for the study of these crucial cellular signaling functions

Light‐Responsive Colloidal Crystals Engineered with DNA

A novel method for synthesizing and photopatterning colloidal crystals via light-responsive DNA is developed. These crystals are composed of 10-30 nm gold nanoparticles interconnected with azobenzene-modified DNA strands. The photoisomerization of the azobenzene molecules leads to reversible assembly and disassembly of the base-centered cubic (bcc) and face-centered cubic (fcc) crystalline nanoparticle lattices. In addition, UV light is used as a trigger to selectively remove nanoparticles on centimeter-scale thin films of colloidal crystals, allowing them to be photopatterned into preconceived shapes. The design of the azobenzene-modified linking DNA is critical and involves complementary strands, with azobenzene moieties deliberately staggered between the bases that define the complementary code. This results in a tunable wavelength-dependent melting temperature (T-m) window (4.5-15 degrees C) and one suitable for affecting the desired transformations. In addition to the isomeric state of the azobenzene groups, the size of the particles can be used to modulate the T-m window over which these structures are light-responsive.N

Light-Responsive Colloidal Crystals Engineered with DNA

A novel method for synthesizing and photopatterning colloidal crystals via light-responsive DNA is developed. These crystals are composed of 10-30 nm gold nanoparticles interconnected with azobenzene-modified DNA strands. The photoisomerization of the azobenzene molecules leads to reversible assembly and disassembly of the base-centered cubic (bcc) and face-centered cubic (fcc) crystalline nanoparticle lattices. In addition, UV light is used as a trigger to selectively remove nanoparticles on centimeter-scale thin films of colloidal crystals, allowing them to be photopatterned into preconceived shapes. The design of the azobenzene-modified linking DNA is critical and involves complementary strands, with azobenzene moieties deliberately staggered between the bases that define the complementary code. This results in a tunable wavelength-dependent melting temperature (T-m) window (4.5-15 degrees C) and one suitable for affecting the desired transformations. In addition to the isomeric state of the azobenzene groups, the size of the particles can be used to modulate the T-m window over which these structures are light-responsive.N