Intramolecular Staudinger Ligation: A Powerful Ring‐Closure Method To Form Medium‐Sized Lactams

Efficient access to medium-sized lactams from ω-amino acids that are resistant to ring-closure by traditional strategies is enabled by an intramolecular Staudinger ligation approach. An undesired premature Staudinger reaction is avoided by protecting the phosphane-containing auxiliary as a borane complex (see scheme; dabco=1,4-diazabicyclo[2.2.2]octane).