A New Versatile Synthesis of Ring‐Substituted 2‐Cyclopropylglycines and Related Amino Acids

Alkyl 2‐chloro‐2‐cyclopropylideneacetates 2 serve as universal starting materials for a new general synthesis of cyclopro‐pylglycines by a simple three‐ to four‐step methodology. 1,4‐Addition of nucleophiles, substitution with azide ion, and mild catalytic deprotection lead to a variety of salt‐free cyclopropyl‐substituted amino acids in good yields, including the natural products 2‐(1‐methylcyclopropyl)glycine (4) and cleonin (5).