Use in inhibiting plant growth of a compound of formula II ##STR1## in which either the pair of symbols X and Y or the pair of symbols Y and Z, together with the carbon atoms to which they are attached, form a non-aromatic ring system having either 5 or 7 ring atoms, all of which are carbon except that one may be oxygen, and which is substituted or unsubstituted, R.sup.1 represents a hydrogen atom or an alkyl, alkenyl or a substituted or unsubstituted phenyl group and R.sup.2 represents a hydrogen atom and R.sup.3 an alkyl carboxyalkyl group or R.sup.2 and R.sup.3 together form a double bond, and thereafter any unsatisfied valencies of ring carbon atoms of the ring shown in formula II are satisfied by hydrogen atoms.
The invention relates to the use of an immobilized transition metal carbonyl complex as a catalyst in the Pauson-Khand reaction and to processes using such as catalyst.
