Derivative 3b, which carries an allyl group in γposition of the ITL heterocycle, was synthesized in an analogous manner. Starting from allyl glycidyl ether 1b, allyl thiirane 2b was obtained in 86% yield (Figure ). The final allyl ITL 3b was obtained in 79% yield by telescoping the ring-opening of 2b with the subsequent acid-mediated cyclization (Figure ). Similar to 3a, 3b is susceptible towards hydrolysis. The latter is successfully supressed by storing the compound at temperatures below 0 °C as shown by kinetic H NMR experiments (ESI, Figure ). With the γ-allyl ITL 3b at hand, we sought to investigate, whether the double bond could be orthogonally functionalized without interference with the reactive ITL heterocycle. Consequently, 3b was subjected to a photo-initiated radical thiol-ene addition as model reaction. Using ethanethiol, the functionalization was successfully carried out in MeCN to give compound 3c, despite low yields of 15% (Figure ). Next, 3b was furnished with a thiol group by following previous reaction conditions in neat 1,2-ethanedithiol. The corresponding thiol-functional ITL 3d was obtained in 53% yield (Figure -23). To demonstrate the coupling of ITL 3b with a polymeric residue, we attached a methoxylated PEG thiol (mPEG-SH) to the allyl double bond using similar conditions. As shown by mass spectrometry data, the PEG-functionalized ITL 3e was successfully detected, along with remains of the starting material mPEG-SH (Table -3, Figure ). On account of the near-equal affinity to the stationary phase, separation of 3e from mPEG-SH via chromatographic means proved to be challenging and optimizations are ongoing. Nonetheless, it was overall demonstrated that (i) γ-functional ITLs can be successfully sourced from glycidol derivatives and (ii) the allyl group of 3b offers further opportunities for functionalization, while no adverse reactions with the heterocycle were observed.