Second region near-infrared (NIR-II) fluorescence imaging has been used widely in vivo due to its long excitation wavelength and the ability to achieve deep penetration depths, and high spatial resolution. However, existing NIR-II fluorescent probes, such as single-walled carbon nanotubes (SWNTs), quantum dots, rare-earth nanoparticles, and other inorganic materials or...

Popular since the early 1900s, the 1,4-addition of Michael donors to activated π-systems (called Michael acceptors) to form new C-C bonds is known as the Michael addition or reaction. With the help of a base, the donor is converted to an enolate ion, which attacks the Michael acceptor. When a...

The Mukaiyama aldol reaction uses a catalytic Lewis acid (e.g. TiCl4) or base, and an aqueous work-up to convert an aldehyde and an E- or Z-enol silane to an anti- and/or syn-diastereomer 1,3-ketol. The aldehyde is activated for nucleophilic attack when it coordinates to the Lewis acid, releasing a chloride...

The use of organozinc reagents in the Negishi (Pd- or Ni-catalyzed) cross-coupling reaction with organohalides allows for a much greater functional group tolerance than in the Kumada cross-coupling reaction. Other benefits include high reactivity, high regio- and stereoselectivity, few side reactions and little toxicity. Unlike the addition of a base...

The oxidation of primary and secondary alcohols with ketones in the presence of metal alkoxides such as aluminum isopropoxide (Al(i-PrO)3) to yield aldehydes and ketones is known as the Oppenauer oxidation. The alcohol substrate binds to aluminum, and the ketone coordinates to it, forming a six-membered transition state that allows...

The cobalt catalyzed formation of cyclopentenones from alkenes, alkynes and carbon monoxide is known as the Pauson-Khand reaction. The precise mechanism has not yet been fully elucidated, but previous studies have demonstrated that the larger alkyne substituent ends up next to the carbonyl group in the product. The regioselectivity with...