R-Butyl chloroformate

XCH2C(CH3)20C0C1, THF, Et3N, H2O, CHCI3, 0°, 1.5 h (X = Br, 41-79% yield X = Cl, 60-86% yield). These halo-substituted r-butyl chloro-formates are more stable than an unsubstituted r-butyl chloroformate. 

Prepuration. Sakai and Anselme recommend that the reagent be prepared by the reaction of r-butyl chloroformate and telramelhylguanidinium azide (2,403-404) ... 

Preparation from 8-hydroxyquinoline, r-butyl chloroformate, and triethylamine in tetrahydrofurane elherat —60° to —25° (yield 72%). With this reagent the preparation of N -protected lysine is particularly easy. 

In contrast to r-butyl chloroformate, which is too unstable to be used, the r-amyl derivative can be stored for over 10 days in a deep freezer at —20°. It is prepared in about 60% yield by reaction of r-amyl alcohol with excess phosgene in ether... 

Preparation of Other Reagents for Boc Protection. Because of its low stability, r-butyl chloroformate has mainly been used... 

Scheme 5.8 Reaction of r-butyl acrylate with chloroform under basic phase transfer conditions...

Symmetrical and unsymmetrical carbonates have also been obtained from the reaction of chloroformates with alcohols under soliddiquid conditions [55], and the reaction of carbamoyl fluorides with alcohols produces alkyl carbamates [58]. r-Butyloxycarbonylation of alcohols and phenols is effected by trans-esterification of di-r-butyl carbonate under basic phase-transfer catalysed conditions [59]. Yields tend to be high for the reaction with the phenols (>85%), but only moderate with the alcohols (30-81%). 

Miscellaneous reactions Allyl chloroformate, 9 1,1 -Carbonyldiimidazole, 66 Di-r-butyl dicarbonate, 94 Di- n-carbonylhexacarbonyldicobalt, 99 Palladium(II) acetate-Triphenylphos-phine, 233... 

Only when a considerable number of large substituents are present do stannylene acetals exist to any extent as the monomer 2,2-dibutyl-4,4,5,5-tetraethyl-l,3,2-dioxastannolane is present almost entirely as the dimer at room temperature in chloroform at 20°C, but the monomer-dimer equilibrium gradually shifts to favor monomer above about 80°C. 2,2-Di-r-butyl-4,4,5,5-tetramethyl-l,3,2-dioxastannolane is a monomer at room temperature.41... 

Allylic C—H oxidation is known to occur if 1,4-dienes are treated with PDC in boiling chloroform (equation 16). hi the presence of r-butyl hydroperoxide, PDC becomes an effective allylic and... 

Kinetic data for some chloro-substituted peresters are given in Table 97. For comparison the kinetic data for t-butyl peracetate are included. The rate of decomposition of r-butyl peroxy chloroformate is about 3 x 10 times greater than... 

Formylpyrazine (25) undergoes the C annizzaro reaction with 40% sodium hydroxide to yield 2-hydroxymethylpyrazine (26) and 2-carboxypyrazine (1077) and with sulfur dioxide in chloroform gave 2-(l -hydroxy-l -sulfomethyl)pyrazine (1077). The preparation of 2,5-di-(hydroxy-r-butyl)pyrazine from 3-amino-2-hydroxy4,4-dimethyltetrahydrofuran has been described in Section II.9 (500). 

Octakis[r-butyl]-l,2,3,4,5-telluratetrastannolane All operations are performed under an argon atmosphere with oxygen-free solvents. Hydrogen telluride is passed for 1 h through a solution of 5.0 g (4.2 mmol) of l,4-diiodo-l,l,2,2,3,3,4,4-oetakis[t-butyl]tetrastannane in a mixture of 100 m/of toluene and 1 ml of triethylamine. The mixture is then filtered to remove preeipitated triethylammonium iodide, the solvent is evaporated from the filtrate, and the residue is recrystallized from chloroform/hexane yield 2.4 g (55%) m.p. 170° (dec.). 

A mixture of isobutane and CCI4 is quite stable at 130 140. If a small amount of / r/-butyl peroxide is added, a reaction occurs, that yields (chiefly) tert-hwiy chloride and chloroform. A small amount of tert-buiy alcohol ((CH3)jCOH, equivalent to the peroxide used) is also isolated. Give all steps in a likely mechanism for this reaction. 

AMINO GROUP f-Amyl chloroformate. r-Butyl azidoformate. 9-Fluorenyl-methyl chloroformate. 

Mixed malonates. Ethyl chloroformate reacts with the a-anion of t-butyl acetate to give ethyl r-butyl malonate in 70-75% yield. The reaction is a general route to mixed malonates. Ethyl chloroformate can be replaced by other... 

Methyl alcohol Ethyl alcohol Butyl alcohol r-Butyl alcohol Ethyl acetate Acetone Chloroform Dimethyl sulfoxide Benzene T oluene... 

---