A deprotonation pathway to reactive [B]=CH2 boraalkenes

The BH compounds IMes(Ar-F)BH(NTf2) (Ar-F : C6F5 or FpXyl) were converted to the IMes(Ar-F)B=CH2 boraalkenes in a three step reaction sequence of B-methylation with methyllithium, hydride abstraction and deprotonation. The B = CH2 boraalkenes reacted with elemental sulfur to give a thiaborirane product. They underwent [2+2] cycloaddition reactions with carbon dioxide or sulfur dioxide to give four-membered boron containing heterocycles. The boraalkenes added strongly Lewis acidic boranes at their = CH2 carbon atoms. The corresponding HB(C6F5)(2)/boraalkene adduct reduced carbon monoxide to a -OCH(C6F5)- moiety inside a five-membered heterocycle at the B-CH2-B template. The boraalkenes reacted with the [(Me2S)AuCl] reagent to form the corresponding (boraalkene)AuCl complexes.