A
titanium catalyst for reaction between a compound having a carbon-carbon unsaturated bond and a compound having an electrophilic functional group or an electrophilic
reagent, said
titanium catalyst being composed of a
titanium compound represented by the formula (1) belowTiX1X2X3X4 (1)(where X1, X2, X3, and X4 denote independently a
halogen atom, C1-20 alkoxyl group, aralkyloxy group, aryloxy group, or —NRxRy group (where Rx and Ry denote independently a C1-20
alkyl group or aralkyl group), and any two of X1, X2, X3, and X4 may form a ring.) and a
Grignard reagent represented by the formula (2) below in a
molar amount 1.5-2.5 times as much as the titanium compound.R1MgX5 (2)(where R1 denotes a C2-10
alkyl group having a
hydrogen atom at the β position and X5 denotes a
halogen atom.)The titanium catalyst of the present invention activates the carbon-carbon unsaturated bond, which has a comparatively low reactivity, thereby catalyzing the reaction with an electrophilic functional group. It is inexpensive and industrially advantageous. When applied to reaction between a compound having a carbon-carbon unsaturated bond and an electrophilic functional group, it yields industrially a variety of adducts of a compound having a carbon-carbon unsaturated bond and a compound having an electrophilic functional group, and it also yields a variety of intramolecular adducts of a compound having a carbon-carbon unsaturated bond and an electrophilic functional group in the same molecule.