Ligand-Enabled β-Methylene C(sp3 )-H Arylation of Masked Aliphatic Alcohols

Despite recent advances, reactivity and site-selectivity remain significant obstacles for the practical application of C(sp³ )-H bond functionalization methods. Here, we describe a system that combines a salicylic-aldehyde-derived L,X-type directing group with an electron-deficient 2-pyridone ligand to enable the β-methylene C(sp³ )-H arylation of aliphatic alcohols, which has not been possible previously. Notably, this protocol is compatible with heterocycles embedded in both alcohol substrates and aryl coupling partners. A site- and stereo-specific annulation of dihydrocholesterol and the synthesis of a key intermediate of englitazone illustrate the practicality of this method.

HFIP-Promoted de Novo Synthesis of Biologically Relevant Nonnatural α-Arylated Amino Esters and Dipeptide Mimetics

Amino acids are fundamental building blocks, which have been extensively used in drug design and organic synthesis. However, nonnatural amino acids are relatively less studied. In this work, the authors report the first HFIP-promoted de novo synthesis of nonnatural α-arylated amino esters and dipeptide mimetics (27 examples, up to 99 % yield) from readily available amines, ethyl glyoxylate and electron-rich arenes under mild conditions, in which one C-C bond, one C-N bond and one chiral center were established simultaneously. The reaction was also performed on a gram scale, giving compound 4 a in 96 % yield. In addition, this protocol was successfully applied to the late-stage elaboration of drug molecules, such as tranylcypromine (TCP or PCPA) and troxipide. Interestingly, compound 4 h inactivated histone lysine specific demethylase 1 (LSD1) potently with an IC₅₀ value of 0.296 μm. To the best of our knowledge, compound 4 h is the first LSD1 inhibitor derived from nonnatural α-arylated amino esters, and therefore could be used as a hit compound for the development of new LSD1 inhibitors. The synthesized nonnatural α-arylated amino esters and dipeptide mimetics as unique building blocks may have potential synthetic utilities.