This invention relates to a method to produce pentfulvenes comprising combining a partially substituted cyclopentadiene with a carbonyl containing compound and lithium or an alkyl lithium, wherein the partially substituted cyclopentadiene is represented by the formula: ##STR1## wherein the R.sup.1 to R.sup.5 groups are independently hydrogen or a C.sub.1 to C.sub.100 group, provided at least one R group is hydrogen but not more than three R groups are hydrogen.