Catalytic [3+2] Annulation of Aminocyclopropanes for the Enantiospecific Synthesis of Cyclopentylamines

With nitrogen too: The first catalytic [3+2] annulation of aminocyclopropanes with enol ethers is reported (see scheme; Phth=phthaloyl). The reaction worked with easily accessible phthalimidocyclopropanes using 5 mol % of SnCl4 in nearly quantitative yields. Polysubstituted cyclopentylamines, which are often present in bioactive compounds, were obtained with high diastereoselectivity and enantiospecificity

Iron-Catalyzed [3+2] Annulation of Aminocyclopropanes with Aldehydes: Stereoselective Synthesis of Aminotetrahydrofurans

The first method for the [3 + 2] annulation of donor acceptor aminocyclopropanes with aldehydes is reported. The reaction is catalyzed by iron trichlorlde on alumina in yields up to 99% and with excellent cis selectivities (up to >20:1) and represents a stereoselective and atom economic access to valuable 2-aminotetrahydrofurans, which constitute the core of DNA and RNA

Diester-Substituted Aminocyclopropanes: Synthesis and Use in [3+2]-Annulation Reactions

In this Letter, we describe the synthesis of new donor-acceptor substituted cyclopropanes bearing various imido groups and their use in [3+2]-annulation reactions. A sequence of palladium-catalyzed vinylation and rhodium-catalyzed cyclopropanation gave access to the required cyclopropanes in only two steps and high overall yields. The obtained compounds were used successfully in the tin-catalyzed [3+2] annulation with enol ethers to give cyclopentylamine derivatives in 22-95% yield

Catalytic Enantiospecific [3+2] Annulation of Aminocyclopropanes with Ketones

The first enantiospecific [3+2] annulation of D-A amino-cyclopropanes with ketones is reported herein (see scheme; Phth = phthaloyl). The reaction is catalyzed by 5 mol % of tin(IV) chloride at -78 °C and gives aminotetra-hydrofurans bearing a C5-quaternary stereocenter in high yield, diastereoselectivity and enantio-specificity

Synthesis of (Carbo) nucleoside Analogues by [3+2] Annulation of Aminocyclopropanes

(Carbo) nucleoside derivatives constitute an important class of pharmaceuticals, yet there are only few convergent methods to access new analogues. Here, we report the first synthesis of thymine-, uracil-, and 5-fluorouracil-substituted diester donor-acceptor cyclopropanes and their use in the indium-and tin-catalyzed [3+2] annulations with aldehydes, ketones, and enol ethers. The obtained diester products could be easily decarboxylated and reduced to the corresponding alcohols. The method gives access to a broad range of new (carbo) nucleoside analogues in only four or five steps and will be highly useful for the synthesis of libraries of bioactive compounds

[4+2]-Annulations of Aminocyclobutanes

The first [4 + 2]-annulation between aminocyclobutanes and aldehydes to access tetrahydropyranyl amines is reported. With phthalimido cyclobutane dicarboxylates and aromatic aldehydes, tetrahydropyrans were obtained in 53-92% yield and 3:1-17:1 dr using scandium triflate or iron trichloride as catalyst. The use of thymine- or fluorouracil-substituted cyclobutanes gave direct access to six-membered ring nucleoside analogues. Finally, the [4 + 2]-annulation between aminocyclobutanes and enol ethers led to the corresponding cyclohexylamines

Taming Hypervalent Bonds and Strained Rings for Catalysis and Synthesis

Improving the synthesis of complex organic molecules is essential for progress in many fields such as medicine, agrochemicals or materials. Since 2007, our laboratory has been focusing on the development of non-classical bond disconnections based on the use of small, energy-loaded organic molecules: hypervalent iodine reagents and strained rings. In this overview article, we report our progress since 2011 in these areas. The use of cyclic hypervalent iodine reagents has been extended to the C2-selective alkynylation of indoles, the domino cyclization alkynylation of allenes, the alkynylation of thiols and the azidation of carbonyl compounds. Amino-substituted aminocyclopropanes and aminocyclobutanes were used in [3+2] and [4+2] annulations to access nitrogen-rich building blocks, including nucleoside analogues. The first example of dynamic kinetic [3+2] annulation of aminocyclopropanes with both enol ethers and aldehydes was also reported

Swiss CAT+, a Data-driven Infrastructure for Accelerated Catalysts Discovery and Optimization

The Catalysis Hub – Swiss CAT+ is a new infrastructure project funded by ETH-domain, co-headed by EPFL and ETHZ. It offers the scientific community a unique integrated technology platform combining automated and high-throughput experimentation with advanced computational data analysis to accelerate the discoveries in the field of sustainable catalytic technologies. Divided into two hubs of expertise, homogeneous catalysis at EPFL and heterogeneous catalysis at ETHZ, the platform is open to academic and private research groups. Following a multi-year investment plan, both hubs have acquired and developed several high-end robotic platforms devoted to the synthesis, characterization, and testing of large numbers of molecular and solid catalysts. The hardware is associated with a fully digitalized experimental workflow and a specific data management strategy to support closed-loop experimentation and advanced computational data analysis