5 mm tci cryogenic probe and z axis gradient

All NMR spectra of all products including deuterated compounds were acquired on a Bruker AVANCE III HD 800 spectrometer equipped with a 5-mm TCI cryogenic probe and Z-axis gradient (Bruker Biospin). All spectra were measured at 25 ºC, using 5 mm NMR tubes. Standard Bruker pulse sequences were employed. The data analyses were carried out with Bruker TopSpin 3.2 software (Bruker Biospin). The acquisition parameters were as follows: ¹H NMR: number of data points 64 K; spectral width 16025 Hz; relaxation delay 10 s; number of scans 64; receiver gain 3.2; ¹³C NMR: number of data points 64 K; spectral width 48077 Hz; relaxation delay 2 s; number of scans 1024; receiver gain 203; ²H NMR: number of data points 64 K; spectral width 4092 Hz; relaxation delay 1 s; number of scans 1024; receiver gain 128. Chemical shift was reported in parts per million (p.p.m.) relative to the peaks from chloroform-d (CDCl₃, δ_H 7.26 p.p.m., δ_C 77.0 p.p.m.). The data for ¹H NMR are reported as follows: chemical shift, multiplicity (s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet), integration and coupling constants.