A concise review covering updated presence and role of 2-phenethylamines in medicinal chemistry is presented. Open-chain, flexible alicyclic amine derivatives of this motif are enumerated in key therapeutic targets, listing medicinal chemistry hits and appealing screening compounds. Latest reports in discovering new bioactive 2-phenethylamines by research groups are covered too.

Ezetimibe is a well-known drug that lowers blood cholesterol levels by reducing its absorption in the small intestine when joining to Niemann-Pick C1-like protein (NPC1L1). A ligand-based study on ezetimibe analogues is reported, together with one-hit synthesis, highlighted in the study. A convenient asymmetric synthesis of (2S,3S)-N-α-(R)-methylbenzyl-3-methoxycarbonylethyl-4-methoxyphenyl β-lactam is described starting from Baylis–Hillman adducts. The route involves a domino process: allylic acetate rearrangement, stereoselective Ireland–Claisen rearrangement and asymmetric Michael addition, which provides a δ-amino acid derivative with full stereochemical control. A subsequent inversion of ester and acid functionality paves the way to the lactam core after monodebenzylation and lactam formation. It also shows interesting results when it comes to a pharmacophore study based on ezetimibe as the main ligand in lowering blood cholesterol levels, revealing which substituents on the azetidine-2-one ring are more similar to the ezetimibe skeleton and will more likely bind to NPC1L1 than ezetimibe.

A convenient asymmetric synthesis of methyl (2S,3S,6R)-6-(4-fluorophenyl)-2-(4-hydroxyphenyl)-piperidine-3-carboxylate is described, starting from Baylis–Hillman adducts. The route involves a domino process: allylic acetate rearrangement, stereoselective Ireland–Claisen rearrangement and asymmetric Michael addition, which provides a δ-amino acid derivative with full stereochemical control. A subsequent chemoselective transformation of one of the side-chain groups allows an effective cyclization leading to biologically interesting polysubstituted piperidines in which the 2,6-aryl groups could be attached sequentially.

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A convenient asymmetric synthesis of (1R,5R,9R)-2-azabicyclo[3.3.1]nonane-9-carboxylic acid is described, starting from (2E,7E)-dimethyl nonadienedioate. The route involves a stereoselective domino Michael-Dieckman process that furnishes a 1,2,3-trisubstituted cyclohexane derivative bearing three adjacent stereocenters with full stereochemical control. A subsequent chemoselective transformation of one of the side-chain ester groups allows an effective second cyclization leading to the morphan motif. The versatility of this novel amino acid for the generation of molecular complexity was tested by elaborating a tripeptide in homogeneous phase.