Thiol-ene reaction
Given the stereoselectivity, high rate and yields, this synthetically useful reaction may underpin future applications in material and biomedical sciences.
This reaction is useful to the field of radical-based photopolymerization because it quantitatively and rapidly proceeds through a simple mechanism under ambient atmospheric conditions.
In the case of norbornene and vinyl ether only step-growth is observed, no homopolymerization occurs after the formation of the carbon centered radical.
The functional groups on the thiol and alkene compounds can affect the reactivity of the radical species and their respective rate constants.
[4] Most time the quasi-first-order reaction yields a kinetic rate equation following the exponential decay function for the reactants and products.
The kinetic curve deviates from the exponential decay function for a common first-order reaction by having a slow growth period.
[9] The use of thiyl radicals as initiators of cyclization has been employed in the synthesis of a number of natural products, including aplysins,[10] α-kainic acid,[11] asperparalines,[12] and alkaloids such as narciclasine and lycoricidine.
When the reverse reaction occurs, the orientation of the hydrogen addition on the carbon radical determines whether the isomerization product will be cis or trans.
Terminal alkene functional groups were added to the dendrimer via esterification by pent-4-enoic anhydride in the presence of DMAP and pyridine.
[2] Given that in aqueous solutions thiol-ene reactions can be initiated by UV light (wavelength 365–405 nm) or sunlight, the attachment of a given functional group to the exposed thiol or alkene can be controlled spatially through photomasking.
Thus, the manipulation of the shape of the photomask and the composition of the aqueous layer results in the creation of heterogeneous surface, whose properties depend on identity of the attached molecule at a given location.
[2] Thiol-ene functionalization of a surface can be achieved with a high level of spatial specificity, allowing the production of photomasks.
Ethoxysilane and methoxysilane functional groups are commonly used to anchor organic molecules on a variety of oxides surfaces.
The thiol-ene coupling can be achieved either in the bulk solution before molecular anchoring [8] or step-wise onto a substrate that enables photolithography.
[8] Thiol-ene can also be used as an electron beam resist,[clarification needed] resulting in nanostructures that allow direct protein functionalization.
