Polar Effects of Organosilicon Substituents in Carboxylic Acids

Synthesis, Structure, and Acidity Constants of Ligated α‐Boryl Acetic Acids

“…Among these are alkyl‐substituted acetic acids, such as butanoic acid, p K a 4.82. Trimethylsilyl acetic acid has a p K a of 5.22 . These comparables are 50–100 times more acidic than the boryl acids in Table .…”

“…Expanding the comparison group to all carboxylic acids, hundreds of p K a values are tabulated, but still few are comparable . Di‐ and especially trisubstituted acetic acids are among the least acidic carboxylic acids.…”

The effect of the trimethylsilylmethyl substituent on ketene cycloadditions

“…2,2-Dichloro-3-trimethylsiIylmethylcyclobutanone (VII). This cycloadduct of dichloroketene and allyltrimethylsilane was vacuum distilled at 65-66 °C (0.025 mm) (54%): IR 1785 cm"1; NMR 0.12 (s, 9 ), 1.20 (8…”

“…Ullman coupling of 6 afforded dimethyl 6,6'-dimethoxy-3,3',5,5'-tetramethyldiphenate (7). Reduction of 7 with L1AIH4 yielded 2,2'-di(hydroxymethyl)-6,6'-dimethoxy-3,3',5,5,-tetramethylbiphenyl (8), which was converted into 2,2'-di(chloromethyll-e.e'-dimethoxy-S.S'.S.S'-tetramethylbiphenyl (9) via the dimesylate of 8. A new phenanthrene synthesis which involved treatment of 9 with sodamide in ammonia afforded 4,5-dimethoxy-1,3,6,8-tetramethylphenanthrene (11) in almost quantitative yield.…”

The Apparent Ionization Constants of Some Organosilylmethylbenzoic Acids

“…For example, Sommer et al (1) reported that the dissociation constant of the acid (CHy)3SiCH2C02H was less than that of acetic acid, and Eaborn and Parker (2) found that the compounds o-, m-, and p-(CH3)3SiCH2C6H4C02H were weaker acids than the corresponding toluic acids. These effects were ascribed to a strong inductive electron supply by the (CH3)3Si group.…”