T-Butyl acetate

Esters and amides may be sulfinylated. Addition of a mixture of t-butyl acetate and sulfinate ester 19 to a THF-ether solution of magnesium diisopropylamide led to the formation of (R)-(+)-f-butyl p-toluenesulfinylacetate (49) in 90% yield (equation 14)7. t-Butyl propanoate and butanoate also underwent this sulfinylation to give 50 and 51 in yields of 68 and 45%, respectively83. The diastereomeric ratio was 1 1 for 50 and 3 7 for 51. These esters may also be obtained by alkylation of 49. Similarly, treatment of a-lithio-A, A -dimethylacetamide with sulfinate ester 19 gave (R)-( + )-N, Ar-dimethyl-p-toluene-sulfinylacetamide (52) (equation 15)84. 

GC assay of the organic layer showed no EIN(TMS)2 remaining after 15 min of stirring (GC conditions Restek RTX-1 column (30 m x 0.53 mm, 1 m film thickness), 2.53 mL/min, initial temperature 50°C, final temperature 300°C, rate 20 deg/min, injection temperature 200°C, detector temperature 350°C, injection volume 1 pL, inject sample neat retention times fert-butyl alcohol 1.4 min, THF 1.7 min, heptane 2.1 min, HN(TMS)2 2.6 min, ethylbenzene (present in commercial LHS) 3.1 min, te/ t-butyl acetate 4.0 min). Volume percents were determined based on standard solution counts. 

The Claisen condensation of t-butyl acetate with a methyl ester is a general route for the preparation of complex P-ketoesters.4 The reaction requires an excess of the enolate of t-butyl acetate to rapidly deprotonate the product and prevent tertiary alcohol formation. Some workers have also used excess LDA or t-butoxide for this purpose. 

The Andersen sulphoxide synthesis allows one also to synthesize a variety of a-heteroatom substituted sulphoxides starting from a-heteroatom stabilized carbanions and (—)-(S)-276. The selected examples shown in Scheme 3 are the best illustration of the generality of this approach. The reaction of enolates or enolate like species with (—)-(S)-276 has been used for the sjmthesis of optically active a-carbalkoxy sulphoxides. For example, treatment of (—)-(S)-276 with the halogenomagnesium enolates of t-butyl acetate, t-butyl propionate or t-butyl butyrate resulted in the formation of ()-(f )-t-butyl p-toluenesulphinylcarboxylates 298 (equation 163). 

Isobutyl acetate t-Butyl acetate Propyl propionate Ethyl butyrate Ethyl isotxityrale Methyl pentanoate Methyl pivalate Paraldehyde... 

Covalently bonded chiral auxiliaries readily induce high stereoselectivity for propionate enolates, while the case of acetate enolates has proved to be difficult. Alkylation of carbonyl compound with a novel cyclopentadienyl titanium carbohydrate complex has been found to give high stereoselectivity,44 and a variety of ft-hydroxyl carboxylic acids are accessible with 90-95% optical yields. This compound was also tested in enantioselective aldol reactions. Transmetalation of the relatively stable lithium enolate of t-butyl acetate with chloro(cyclopentadienyl)-bis(l,2 5,6-di-<9-isopropylidene-a-D-glucofuranose-3-0-yl)titanate provided the titanium enolate 66. Reaction of 66 with aldehydes gave -hydroxy esters in high ee (Scheme 3-23). 

In the case of t-butyl acetate, shown in reaction 41, three successive geminal hydrogen abstractions and insertions of 303 take place a product of reductive dimerization (306) is also formed in small yield626. 

A recent example of a chemical study showing how strain effects could be important in an enzymatic reaction, dealt with the hydrolysis of benzaldehyde di-t-butyl acetal [18] (Anderson and Fife, 1971b). As shown by a Stuart-Briegleb model, substantial ground-state strain is present which would be partially relieved in the... 

Benztddehyde di-t-butyl acetal [18] has an aliphatic alcohol leaving group, but the bond breaking process is aided by relief of ground... 

State strain [68]. The general acid catalysis observed with t-butyl acetals (a = 0-6) (and not detectable with the analogous diethyl acetals) is attributable primarily to greater ease of bond breaking. 

Butoxy ethanol sec-Butyl acetate t-Butyl acetate n-Butyl acetate sec-Butyl alcohol t-Butyl alcohol n-Butyl alcohol n-Butyl glycidyl ether p-tert-Butyl toluene... 

As indicated in Scheme 27, indoles may be alkylated by their acid-catalyzed reaction with alcohols. Similarly, r-butylation of pyrroles has been effected by the acid-catalyzed reaction with t- butyl acetate (B-77MI30502), and the diarylmethylation of 1-methylpyrrole from the acid-catalyzed reaction with the chromium trichloride complex of the diarylcarbinol has been described (78JA4124). The alkylation of indoles by alcohols in the presence of the aluminum alkoxide and Raney nickel appears to be efficient for the synthesis of 3-substituted indoles, but is less successful in the alkylation of 2-methylindole (79JHC501). The corresponding isopropylation of pyrrole produces 2,5-diisopropylpyrrole and 1-isopropylpyrrolidine, as the major products (79JHC501). 

A new and efficient method for the synthesis of optically active esters and lactones having a tertiary or a quaternary stereogenic centre at the y -position has been developed.28 Treatment of optically active 1-chlorovinyl p-tolyl sulfoxides having two different substituents at the 2-position with the lithium enolate of t -butyl acetate gave optically active adducts in 99% chiral induction from the sulfur stereogenic centre. 

Enantioselective aldol reaction -hydroxy esters.2 The lithium enolate 4 of t-butyl acetate reacts with an aldehyde in the presence of 2 to form P-hydroxy esters 6 in 90-96% ee. 

The reference cited [5] also gives procedures for related magnesiations of other carboxylic acids, phenylacetronitrile, t-butyl acetate, acetophenone, methyl phenyl sulfone, and diethyl phenyl-methanephosphonate. 

Anionic micellar systems were found to increase the rate of the acid catalyzed hydrolysis of acetylsalicylic acid (Nogami et al., 1962), methantheline bromide (Nogami and Awazu, 1962), n-butyl acetate, t-butyl acetate, ethyl p-aminobenzoate, and ethyl o-aminobenzoate (Sakurada et al., 1967), but decreased that of methyl benzoate slightly (Sakurada et al., 1967). The acid catalyzed hydrolysis of anionic amphi-philes also generally tend to be accelerated by micellization (Table 5). The rates of the acid catalyzed hydrolyses of sodium sulfoethyl do-decanoate, sodium undecanoate, and sodium sulfobutyl caprylate are significantly greater in micellar than in non-micellar solutions while that of sodium dodecyl sulfoacetate is unaffected by micelle formation (Meguro and Hikota, 1968). 

N,N-dimethylformamide-di-t-butyl acetal has also been used to prepare by the author (1) to prepare other Step 4 derivatives illustrated in Eq. 1 ... 

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