Ethers unsymmetrical aliphatic

Answer VII-c is an unsymmetrical aliphatic etlicr (I -methyl cyclohexyl ethyl ether). 

Reactions of unsymmetrical methylene 1,3-dicarbonyl compounds with enol ethers have been investigated by Yamauchi et al. [137]. As we have mentioned earlier, the a,/ -unsaturated ketone moiety in alkylidene-/ -ketoesters reacts exclusively as the oxabutadiene. However, high regioselectivity is also observed with mixed alkyl-phenyl-1,3-diketones with exclusive reaction of the aliphatic carbonyl group, whereas in alkylidene-1,3-dicarbonyl compounds bearing an aldehyde and a keto-moiety, the a,/J-unsaturated aldehyde reacts preferentially as oxabutadiene, but not exclusively [130a]. 

Template reactions between malonaldehydes and diamines in the presence of copper(II), nickel(II) or cobalt(II) salts yield neutral macrocyclic complexes (equation 15). Both aliphatic and aromatic diamines can be used. In certain cases, non-macrocyclic intermediates can be isolated and subsequently converted into unsymmetrical macrocyclic complexes by reaction with a different diamine (Scheme 11). These methods are more versatile and more convenient than an earlier template reaction in which propynal replaces the malonaldehyde (equation 16). This latter method can also be used for the non-template synthesis of the macrocyclic ligand in relatively poor yield. A further variation on this reaction type allows the use of an enol ether (vinylogous ester), which provides more flexibility with respect to substituents (equation 17). The approach illustrated in equation (15), and Scheme 11 can be extended to include reactions of P-diketones. The benzodiazepines, which result from reaction between 1,2-diaminobenzenes and P-diketones, can also serve as precursors in the metal template reaction (Scheme 12). The macrocyclic complex product (46) in this sequence, being unsubstituted on the meso carbon atom, has been shown to undergo an electrochemical oxidative dimerization (equation 18). ... 

Unsymmetrical ethers can be prepared by dehydration of aliphatic alcohols only when one reactant is a tertiary alcohol 660 sulfuric acid is often the condensing agent in such cases. 

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