In recent years, Fluorous chemistry has emerged as one of the promising fields of green chemistry. The term "fluorous" is a coined word meaning having affinity with fluorocarbons. Highly fluorinated compounds, in another words fluorous compounds, are insoluble in general organic solvents or water. However they are highly soluble with fluorous solvents such as perfluoroalkane. Fluorous chemistry is the technique of making use of this property, and it is applied to many organic reactions. Although fluorous solvents are generally immiscible with common organic solvents and water, certain fluorous solvents are able to form homogeneous solutions with some organic solvents at elevated temperatures. The characteristic features of these fluorous solvents is that they have boiling points properties that are almost equal to those of the corresponding hydrocarbons, regardless of their molecular weight, and these solvents have a high solubility of many gases and incombustible property. Taking the advantage of these properties, Horváth et al. accomplished the hydroformylation of olefins using a fluorous rhodium catalyst in perfluoromethylcyclohexane and toluene in 1994.¹⁾ This was regarded as the origin of the fluorous chemistry. This reaction uses perfluoromethylcyclohexane and toluene as solvents, which exist as a biphasic system at room temperature. In this system the fluorous catalyst exists in the fluorous phase and the olefins in the organic phase. However, the two phases form a homogeneous solution when heated. The reaction then proceeds by introduction of carbon monoxide and hydrogen gases. When the reaction is complete and the system is cooled, the two phases reappears, where the resulting product is found in the organic phase and the fluorous catalyst is in the fluorous phase; thus, the catalyst and the product are easily separated. The biphasic system using a fluorous solvent and an organic solvent is called Fluorous Biphase System (FBS), and the multiple phase system is called Fluorous Multiphase System (FMS). The advantages of FBS and FMS are that the resulting product and the catalyst can be easily separated simply by separating the fluorous phase from the other phase after the reaction. After separation, the fluorous phase containing the fluorous catalyst can be reused.

Curran et al. have introduced the use of fluorous substituents (fluorous tags) into non-fluorous substrates for the synthesis of isoxazoline.²⁾ After the reaction, the fluorous product was separated by fractional extraction with dichloromethane, water, and perfluorohexane. Following this report, numerous applications of fluorous chemistry have been made in combinatorial chemistry³⁾ and oligosaccharide syntheses.⁴⁾

Fluorous Solvents

Fluorous Compounds

Fluorous Solvents

D2669	T0439	E0485
H0946	H0085	P0837
P1420	P0851	P0856
T1012

Fluorous Compounds

P1081	P1102	P1080
H1056	H1058	E0462
B2340	D2804	H0845
A1330	N0600	P1155
H0846	O0318	D1101
P0904	T1701	D2891
O0294	T0829	T0828
N0601	P1106	T2037
D2333	D2465	N0689
P1363	H0844	H1038
H1176	P1084	H0843
H0781	H0729	H0892
H1057	P1452	P1453
U0071	N0645	P1162
P1163	N0607	N0677
N0499	N0605	D2329
O0260	P0764	P1098
N0712	T1545	T1098
T1770	U0067