Esters in Nature Waxes, Fats, Oils, and Lipids

Grignard reagents add twice to give tertiary alcohols (or secondary alcohols, from formates). Lithium aluminum hydride reduces esters all the way to alcohols, whereas bis(2-methylpropyl)aluminum (diisobutylaluminum) hydride allows the process to be stopped at the aldehyde stage. With LDA, it is possible to form ester enolates, which can be alkylated by electrophiles. 

ESTERS IN NATURE WAXES, FATS, OILS, AND LIPIDS 

Esters are essential components in the cells of aU living organisms. This section introduces several of the most common types of natural esters with brief descriptions of their biological functions. 

Waxes are simple esters, whereas fats and oils are more complex 

Extraction of biological material with nonpolar solvents gives a wide assortment of compounds that includes terpenes and steroids (Section 4-7), fats and oils, and a variety of other low-polarity substances collectively called lipids (lipos, Greek, fat). Lipid fractions include phospholipids, important components of cell membranes, which are derived from carboxylic acids and phosphoric acid. In the phosphoglycerides, glycerol is esterified with two adjacent fatty acids and a phosphate unit that bears another substituent derived from a 

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Esters in Nature Waxes, Fats, Oils, and Lipids CHAPTER 20... 

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