This review is focused on the recent development of methodologies for the introduction of a difluoromethylene unit into organic compounds by direct fluorination or indirect fluorination (building-block) methods. As methods for direct fluorinatio, the use of both nucleophilic and electrophilic fluorinating agent for the introduction of a -CF~2- group has been discussed. As indirect method, the use of new -CF~2- containing building blocks in the synthesis of -CF~2- containing compounds has been summarized.

Key words: ELECTROPHILIC REACTION, NUCLEOPHILIC REAGENTS, NUCLEOPHILIC REACTION, FLUORINE, FREE RADICAL REACTION, FLUORINATION REACTION, FLUORIDE, REARRANGEMENT REACTION, METHYLENE