The reaction of 1 with compounds containing 4-6 membered methylidene cycloalkane rings (3b-d) was investigated (Scheme 1). For the substrates containing 5 and 6-membered rings after heating at 100 °C overnight, hydromagnesiated products 4c and 4d and were isolated in high yields (> 80%). The reaction occurs exclusively with anti-Markovnikov addition of the Mg-H bond of 1 to the alkene. The products were characterised by a diagnostic Mg-CH2 unit in the 1 H NMR spectrum in d6-benzene solution, H = -0.07 and -0.18 ppm for 4c and 4d