ZrCp2(isoprene) reacts with aliphatic aldehydes, ketones or nitriles regioselectively on C1-carbon of the isoprene moiety to give novel 2-oxa- or 2-aza-metallacycles which release alcohols or ketones respectively on hydrolysis. In contrast, ZrCH3(η1-methylallyl)Cp2, Ti(η3-methylallyl)Cp2, and [MgCH2C(CH3)=CHCH2]n reacted with acetone on the C3-carbon of the methylallyl or the isoprene unit.

A series of isoprene coupling dimers bonded at 1-2, 1-3, 1-4, 2-4, 3-4, or 4-4 position was prepared by regiocontrolled catalysis of trasition metals or without catalysts in the reaction of 2-methyl-2-butene-1,4-diylmagnesium or 3-methyl-2-butenylmagnesium chloride with C5-alkenyl halides.