1,2-dibromocyclohexane synthesis

A facile synthesis of carba- -D-glucopyranose (99) and its l antipode (104) was accomplished by means of resolution of the starting compound DL-( 1,3,5/2,4)-2,3-diacetoxy-4,5-dibromocyclohexane-1 -carboxylic... 

The ITIES with an adsorbed monolayer of surfactant has been studied as a model system of the interface between microphases in a bicontinuous microemulsion [39]. This latter system has important applications in electrochemical synthesis and catalysis [88-92]. Quantitative measurements of the kinetics of electrochemical processes in microemulsions are difficult to perform directly, due to uncertainties in the area over which the organic and aqueous reactants contact. The SECM feedback mode allowed the rate of catalytic reduction of tra 5-l,2-dibromocyclohexane in benzonitrile by the Co(I) form of vitamin B12, generated electrochemically in an aqueous phase to be measured as a function of interfacial potential drop and adsorbed surfactants [39]. It was found that the reaction at the ITIES could not be interpreted as a simple second-order process. In the absence of surfactant at the ITIES the overall rate of the interfacial reaction was virtually independent of the potential drop across the interface and a similar rate constant was obtained when a cationic surfactant (didodecyldimethylammonium bromide) was adsorbed at the ITIES. In contrast a threefold decrease in the rate constant was observed when an anionic surfactant (dihexadecyl phosphate) was used. 

More recently, a facile synthesis of 126 and pseudo-a-L-glucopyranose (137) has been described [32], When the bromolactone 38 was heated with glacial acetic containing hydrogen bromide and subsequently acetylated, DL-(l,3,5/2,4)-2,3-diacetoxy-4,5-dibromocyclohexane-l-carboxylic acid (130) was obtained [31], Resolution of 130 with optically active a-methylbenzylamines provided the enantiomer (131), m.p. 

Suppose, for example, that we must synthesize 1,2-dibromocyclohexane from cyclohexanol, a cheap and readily available starting material. Because there is no way to accomplish this transformation in one step, this synthesis must have at least two steps. 

Cyclohexene is called a synthetic intermediate, or simply an intermediate, because it is the product of one step and the starting material of another. We now have a two-step sequence to convert cyclohexanol to 1,2-dibromocyclohexane. and the synthesis is complete. Take note of the central role of the alkene in this synthesis. 

An SECM study of electrochemical catalysis at the ITIES was based on a similar concept [31]. The ITIES was used as a model system to study catalytic electrochanical reactions in microemulsions. Microemulsions, that is, microheterogeneous mixtures of oil, water, and surfactant, appear attractive for electrochemical synthesis and other applications [91]. The ITIES with a monolayer of adsorbed surfactant is of the same nature as the boundary between microphases in a microemulsion. The latter interface is not, however, directly accessible to electrochemical measurements. While interfacial area in a microemulsion can be uncertain, the ITIES is well-defined. A better control of the ITIES was achieved by using the SECM to study kinetics of electrochemical catalytic reduction of trani -l,2-dibromocyclohexane (DBCH) by Co(I)L (the Co(I) form of vitamin 6,2) ... 

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