Derivatives of Diols

Plasticizers. About 2.5% of U.S. adipic acid consumed in 1988 was used in two basic types of adipic ester based plasticizers (195). Simple adipate esters prepared from Cg—alcohols are used especially as PVC plasticizers (qv). Eor special appHcations requiring low volatility or extraction resistance, polyester derivatives of diols or polyols are preferred. 

Mono MOM derivatives of diols can be prepared from the ortho esters by diiso-butylaluminum hydride reduction (46-98% yield). In general, the most hindered alcohol is protected. ... 

The DTBS group is probably the most useful of the bifunctional silyl ethers. Di-methylsilyl and diisbpropylsilyl derivatives of diols are very susceptible to hydrolysis even in water and therefore are of limited use. 

Several macrocyclic dilactones such as 80 were prepared by reaction of dicarboxylic acid difluorides (e.g. 78) with triphenyltin derivatives of diols (e.g. 79) in excellent yields [63]. The required acid fluorides can be synthesized by reaction of the acids with 2-fluoro-iV-methylpyridmiumtosylate (81) and addition of triethylamine. The triphenyltin derivatives of the diols were prepared in situ from PhsSn—O—SnPh3 and the diols. 

The optimum catalyst for cycloaddition of the A -crotyl dienophile 175 with cyclopentadiene was found to be that generated from diethylaluminum chloride and diol 187. On this basis, the reactions of dienophiles 189 and 181 were examined with cyclopentadiene and furan as indicated in Sch. 20. In addition, catalysts derived from two derivatives of diol 187 were also examined, as shown in Table 11 [43-45]. It was found that all three diols resulted in similar asymmetric induction, with the highest induction not exceeding that observed for the A -crotyl dienophile 175. The A -acrolyl dienophile 189 gave an 83 17 mixture of endo and exo diastereomers, with 21 % ee for the endo adduct, with a catalyst prepared from diol 187. The same catalyst gave 25 % ee for the cycloadduct of furan with 189 and 2 % ee for the adduct of cyclopentadiene and 191, although in the latter example an increase to 27 % ee is possible with sub-stoichiometric amounts of catalyst. 

Polycondensation of dicarboxylic acids with derivatives of diols (e.g., acetates of bisphenols), or... 

Isolation of the Alkyl Ethers of Polyhydric Alcohols. The ethers of long-chain alcohols with glycerol are widely distributed in nature in the form of esters with fatty acids these are the neutral lipids and phospholipids corresponding derivatives of diols probably occur also. Alkaline hydrolysis of the ester groups in alkoxylipids cannot be recommended since it is difficult to extract glycerol alkyl ethers completely from aqueous solutions of fatty acids. The alkyl ethers of polyhydric alcohols are best liberated from their acyl derivatives by methanolysis (see above) or by reduction with lithium aluminium hydride. 

---