Reverse phase transfer: transferring reagents and/or catalysts to the aqueous phase
Phase transfer chemistry

O-Alkylation (etherification, esterification, transesterification)

N-Alkylation

C-Alkylation

S-Alkylation

Alcohol oxidation, alkene epoxidation

Reduction (borohydride)

Hydrohalogenation, dehydrohalogenation

Polymerization (polycarbonate, epoxy resin)

Michael's addition

Aldolization

Darzens' reaction

Knoevenagel's reaction

Reaction from Wittig and Horner-Emmons

Reaction of carbenes (insertion of dichlorocarbenes, preparation of isonitriles)

Metal-catalyzed reactions (carbonylation, oxidation, carbon-carbon coupling, reduction)

...