Transition-metal catalyzed X--H insertions from linebreak α-diazocarbonyl compounds represent one of the most efficient approaches to form C--X bonds. The presented thesis is based on the synthesis and application of linebreak α-diazocarbonyl compounds in metal-catalyzed N--H insertion and the chemoenzymatic synthesis of heterocycles via a [Cu]/[Rh] catalyzed intramolecular O--H insertion. [0.7ex] In the first part, a straightforward approach via the Wittig reaction, γ-Umpolung addition and diazo transfer reaction allowed the synthesis of unsaturated α-diazocarbonyl compounds with ease. [0.7ex] In the second part, the newly synthesized (R textsubscript{p)-pseudo-ortho [2.2]paracyclophane-based bisoxazoline ligands presented superior reactivity. The obtained δ-amino linebreak α,β-unsaturated carboxylic esters were used to synthesize hexahydroindoles, which are key intermediates in the synthesis route of Rostratin B--D. [0.7ex] Additional investigation of α-diazocarbonyl compounds led to the enzymatic synthesis of O-Heterocycles. With the employment of enantiopure starting material obtained from ketoreductase LbADH, the enantioselectivity of each diastereomer from the O--H insertion product have been effectivity improved. weiterlesen