Adamantyl

Although it is not a reaction of alkenes, oxidation of some alkanes with Pd(ll) is cited here. 1-Adamantyl Irilluoroacetate (155) was obtained in above 50% yield by the reaction of adamantane with Pd(OAc)2 in trifluoroa-cetic acid at 80 C[171]. 

Tertiary alkyl chlorides have been converted to the tertiary nittiles with trimethylsilyl nittile ia dichioromethane ia the presence of SnCl (131). The reaction was appHed to the synthesis of several bridgehead nittiles, such as 1-adamantyl and 1-diamantyl nittiles from the corresponding chloro or bromo derivatives usiag SnCl or AIBr. catalysts (132). 

Many carbamates have been used as protective groups. They are arranged in this chapter in order of increasing complexity of stmcture. The most useful compounds do not necessarily have the simplest stmctures, but are /-butyl (BOC), readily cleaved by acidic hydrolysis benzyl (Cbz or Z), cleaved by catalytic hy-drogenolysis 2,4-dichlorobenzyl, stable to the acid-catalyzed hydrolysis of benzyl and /-butyl carbamates 2-(biphenylyl)isopropyl, cleaved more easily than /-butyl carbamate by dilute acetic acid 9-fluorenylmethyl, cleaved by /3-elimination with base isonicotinyl, cleaved by reduction with zinc in acetic acid 1-adamantyl, readily cleaved by trifluoroacetic acid and ally], readily cleaved by Pd-catalyzed isomerisation. 

Adamantyl Carbamate (Adoc-NRf R2NC02-l-adamantyl Formation... 

Adamantyl bromide [768-90-1] M 215.1, m 117-119", 118", 119.5-120". If coloured, dissolve in CCI4, wash with H2O, treat with charcoal, dry (CaCl2), filter, evap to dryness. Dissolve in a small volume of MeOH and cool in a C02/trichloroethylene bath and collect the crystals. Sublime at 90-100°/water pump vacuum. [Chem Ber 92 1629 1959 J Am Chem Soc 83 2700 1961.]... 

Adamantyl bromomethylketone [5122-82-7] M 257.2, m 76-79", 78-79". Dissolve in Et20, wash with H2O, dry (MgS04>, evaporate and crystallise residue from small volumes of MeOH. LACHRYMATORY. [Chem Ber 93 2054 I960.]... 

Adamantyl fluoride (1-fIuoroadamantane) [768-92-3] M 154.2, m 210-212" (dec), 259-260" (dec). Dissolve in Et20, dry over Na2S04 evaporate to dryness and sublime the residue at 90-100°/12mm. Recryst sublimate from MeOH, m 259-260°. [Zh Org Khim 30 1609 1965.] To remove 1-hydroxyadamantane impurity, dissolve in cyclohexane cool for many hours, filter off the hydroxyadamantane, and evaporate to dryness. Recrystallise the residue from pet ether at -77° and sublime in vacuum, m 210-212° dec (sealed tube). [J Org Chem 30 789 1965.]... 

Adamantyl isocyanate [4411-25-0] M 177.3, m 144-145". Recryst from n-hexane and sublime. Irritant. [Chem Ber 95 2302 1962.]... 

Carbonylation ot 1-adamantyl triflate in the presence of tnflic acid also gives a derivative of homoadamantane as the result of a similar rearrangement with ring expansion [55] (equation 36)... 

The Bum derivative has been used to protect the r-nitrogen of histidine to prevent racemization during peptide bond formation. The related 1-adamantyl-oxymethylamine has been used similarly for histidine protection. 

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