The auto-initiated high temperature acrylate polymerization represents a versatile route for the synthesis of macromonomer building blocks. Various macromonomers were synthesized via this route based on methyl, ethyl, n-butyl, t-butyl, 2-ethylhexyl, isobornyl and 2-[[(butylamino)carbonyl]oxy]ethyl acrylate. The synthesis requires a temperature of 140 °C and is carried out in a 5 wt.-% solution of hexyl acetate. The macromonomer library is fully characterized via electrospray ionization mass spectrometry (ESI-MS). The amount of macromonomers containing the geminal double bond lies in between 82 and 95%, depending on the monomer type. The achievable molecular weight of the macromonomers is located between 800 and 2 000 g·mol−1 with a polydispersity of close to 1.6. In addition, it is demonstrated that radical initiators are useful add-ons (to circumvent the inhibition time observed during initiator-free synthesis) without interfering in the actual polymerization as no initiator-fragment containing products are identified via high resolution mass spectrometry.