(i) Me2SnH2, hexane, (ii) /BRN= 2243576/; Multistep reaction;

in 1,3,5-trimethyl-benzene under N2, mixt. of educts in mesitylene heated at 170-175°C for 7 d; filtered through Al2O3, washed with CH2Cl2, evapd. at 50°C/1E-4 bar, crystd. from CH2Cl2/pentane, chromd.(Al2O3/4percent H2O, pentane-Et2O), crystd. from pentane; elem. anal.;