General Synthesis of Conformationally Constrained Noncanonical Amino Acids with C( sp 3 )-Rich Benzene Bioisosteres.

Recent years have seen novel modalities emerge for the treatment of human diseases resulting in an increase in beyond rule of 5 (bRo5) chemical matter. As a result, synthetic innovations aiming to enable rapid access to complex bRo5 molecular entities have become increasingly valuable for medicinal chemists' toolkits. Herein, we report the general synthesis of a new class of noncanonical amino acids (ncAA) with a cyclopropyl backbone to achieve conformational constraint and bearing C( sp 3 )-rich benzene bioisosteres. We also demonstrate preliminary studies toward utilities of these ncAA as building blocks for medicinal chemistry research.