Linker Strategies in Modern Solid‐Phase Organic Synthesis

Method for Activation and Recycling of Trityl Resins

“…10 was obtained as a colorless liquid in 74% yield (47 mg, 0.38 mmol). 1 H and 13 C NMR data were in agreement with published data. 6 Anal.…”

“…A crucial feature of solid-phase synthesis is the attachment of the substrate to the polymeric support. 1 The first building block has to be attached efficiently, the linkage has to be stable to the subsequent chemical transformations, and conditions for release from the support should be compatible with the final products. Commonly these linker groups are based on standard protecting groups used in traditional solution-phase synthesis.…”

“…Commonly these linker groups are based on standard protecting groups used in traditional solution-phase synthesis. Trityl groups 1,2 are often used in this context and can serve as protecting groups for alcohols, acids, amides, amines, amino acids, hydroxamic acids, imidazoles, nucleotides, thiols, and thioureas. 1−3 Using a trityl linker in solid-phase synthesis allows the "protected" compound to be subjected to various chemical manipulations followed by release to afford pure compounds without the need for numerous purification steps.…”

Automated Chemical Oligosaccharide Synthesis: Novel Approach to Traditional Challenges

“…Due to its labile nature, the linker itself has to be taken into account for orthogonality in respect to all protecting (or leaving) groups that will be manipulated during the various steps. For the same reason, various linkers stable under many different conditions have been developed for carbohydrate synthesis. , In addition to known and widely used protecting group-derived linkers, such as succinoyl, alkoxybenzyl, and silyl-based linkers, a new wave of photoreactive, metathesis, or hydrogenation-removable linkers had emerged. ,− In the subsequent effort to develop new linkers with a versatile installation and/or removal profile, recent developments included Reichardt’s spacer/linker, as well as Seeberger’s “Lenz linker,” safety catch linker, and photocleavable linker . Some examples of recently developed linkers are summarized in Figure .…”

Solid-Supported Hydrazone of 4-(4′-Formyl-3′-methoxyphenoxy)butyric Acid As a New Traceless Linker for Solid-Phase Synthesis

“…Hydrazone linkers belong to a very important group of traceless linkers. 22,12 Several possible cleavage conditions for hydrazones exist depending on the desired product. Reduction with borohydride leads to alkane products, whereas basic conditions afford alkenes.…”