Acyclic alkanes synthesis

Alkane synthesis via coupling of organoboranes was discovered very early during the development of organoborane chemistry. The procedure is simple and involves the hydroboration of an alkene followed by treatment with basic silver nitrate (equations 108-110). Both acyclic and cyclic alkanes can be prepared through this procedure. 

Radical addition of dibromodifluoromethane to alkenes followed by sodium borohydride reduction is a convenient two-step method for the introduction of the difluoromethyl group.5 Either one or both carbon-bromine bonds in the intermediate dibromides may be reduced, depending on the reaction conditions. In the case of acyclic dibromodifluoromethane-alkene adducts, the reduction occurs regioselectively to yield the relatively inaccessible bromodifluoromethyl-substituted alkanes. The latter are potential building blocks for other fluorinated compounds. For example, they may be dehydrohalogenated to 1,1-difluoroalkenes an example of this methodology is illustrated in this synthesis of (3,3-difluoroallyl)trimethylsilane. 

Alkanes and cycloalkanes. Obviously a variety of acyclic and cyclic hydrocarbon structures can be synthesized from the appropriate alkyl- or aryl-thiophenes (Scheme 46). The reaction is especially useful for the construction of macrocycles (Scheme 47). One of the most interesting applications of this reaction is in the synthesis of the chiral hydrocarbon butylethylmethylpropylmethane (210) (80JOC2754). The chiral acid (209) was the precursor, in which the thiophene was the potential n-butyl group. Raney nickel desulfurization, followed by standard manipulations to convert the acetic acid unit into an ethyl group, gave the hydrocarbon (210) (Scheme 48) this had [a]578 = -0.198°. It was established that... 

Silyl ketene acetal adds photolytically to C50 give a-fullerene-substituted carboxylic esters and are used in L-quebrachitol and statine synthesis They induce the first highly asymmetric Pummerer-type reaction of acyclic sulphoxides, giving siloxy(arylthio)alkanes with >99% ee541. 

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