Butene, pivalic acid

For example, industrially, pivalic acid is prepared from CO and butene isomers at 80°C and 20-100 atm (Koch synthesis). ... 

E)- and (Z)-4-Benzyloxy-3-hydroxy-l-(4-methylphenyl)-l-butene gave, with triethyl orthoacetate in the presence of pivalic acid, the same, but enantiomeric, (R,E) and (.S , )-6-benzyloxy-3-(4-methylphenyl)-4-hexenoate [5 65%, 87% ee from the (E -butene R 78%, 90% ee from the (Z)-butene] (see p 3374)288. Similarly, (R,E)- and (S, )-6-benzyloxy-3-(4-methylphenyl)-4-hexenal are obtained by heating the (E)- and (Z)-butenes with excess methyl vinyl ether in the presence of mercury(II) acetate in a sealed tube [S 72 %, 90 % ee from the (E)-butene R 71 %, 85% ee from the (Z)-butcnc]288. Analogous strategies have been used to construct the phytyl side chain of tocopherol (see p 3370)289,290. 

Koch Reacdon. C-6-neoacids are readily available from amji alcohols by the Koch reaction. Greater than 95% 2,2-dimethylbutyric acid [595-37-9] was obtained from 2-meth5i-1-butene at 304 kPa (3 atm) CO and 35°C for 1 h with cupric oxide and sulfuric acid catalyst (31). Likewise, 2,2-dimethylbutyric acid can be obtained in high yidd (75—80%) from 1- or 2-pentanol or neopentyl alcohol from the Koch-Haaf reaction (32,33). tert-Amy. alcohol gives a mixture of trimethyl acetic acid [75-98-9] (pivalic acid), 2,2-dimeth5ibutyric acid, C-7 acids, and C-11 acids under similar Koch-Haaf conditions (33). 

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