2-Adamantyl fluoride

Adamantyl alcohol, 58, 78 2-Adamantyl fluoride, 58, 78 Adipic acid, 56, 70... 

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.]... 

Fluoroacetamide [640-19-7] M 77.1, m 108°. Crystd from chloroform. 1-Fluoroadamantane see 1-adamantyl fluoride. 

Oxidative fluorination of alkyl- or aryl-phosphines R PH3 for R = Ph, C6Hu, or NCCH2CH2 occurred on reaction with xenon difluoride, but with the chlorides Ph PCl3 there was also chlorine substitution, and the products were the normal phenyl fluorophosphoranes. In the presence of PhPp4, phosphorus trifluoride can be inserted into the C—F bond of 1-adamantyl fluoride to produce the previously inaccessible l-adamantyltetrafluorophosphorane ° substitution of PF3 by Bu Pp2 or 1-adamantyldifluorophosphine led to, respectively, 1-adamantyl-t-butyl-trifluorophosphorane and bis( 1 -adamantyl)trifluorophosphorane. 

The 2-methyl, 2-cyclopropyl and 2-phenyl substituted 8,9-dehydro-2-adamantyl cations 25 were prepared from their respective alcohols using fluorosulfuric acid in sulfuryl chloride fluoride at low temperatures (equation 27). The relative extent of charge delocalization in these cations was estimated by comparing their NMR spectra. The ions are nonequilibrating static cations, as shown by their proton NMR spectra56. 

Many carbamates have been used as protective groups. They are, for the most part, arranged in this chapter in order of increasing complexity of structure. The most useful compounds (not necessarily the simplest structures) are /-butyl (BOC), readily cleaved by acidic hydrolysis benzyl (Cbz or Z), cleaved by catalytic hydro-genolysis 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 allyl, readily cleaved by Pd-catalyzed isomerization or by nucleophilic addition to the tt-allylpalladium complex and trimethylsilylethyl, cleaved with fluoride. 

Scheme 14 Palladium-catalyzed cross-coupling of (hetero)aryl triflates with fluoride employing the (L5) Pd (COD) pre-catalyst. Ad = I-adamantyl COD= 1,5-cychoctadiene...

Peptide synthesis, N-protection Acetic-formic anhydride. Adamantyl chloroformate. Benzylthiocarbonyl chloride. /-Butoxycarbonyl-N-hydroxysuccinimide ester. /-Butyl azido-formate. /-Butylcarbonic diethylphosphoric anhydride. /-Butyl fluoroformate. /-Butyl oxycarbonyl fluoride. /-Butyl pentachlorophenyl carbonate. /-Butyl 2,4,5-trichlorophenyl carbonate. Carbobenzoxy chloride. 3,5-Dimethoxybenzyl p-nitrophenyl carbonate. [2-(Diphenyl)isopropyljphenyl carbonate. /-Pentyl chloroformate. 

Fig. 40. Chemiluminescent decomposition of adamantyl aromatic dioxetanes by fluoride-induced cleavage of silyl ether side chains. The 2,6-substitution pattern shown in (a) has a quantum efficiency of 0.01%, whereas the 2,4-substitution pattern shown in (b) has a quantum efficiency of 45%. The data [which are taken from the work of Schaap et al. (S8)] can be rationalized by considering the mechanism suggested in Fig. 39.

The fluoride ion in the tetraaza analogue of the fenestrane related phosphonium fluoride (158) is an example of a completely ionic fluoride ion <81JA5265>. The ozonide (159) from an adamantyl type phosphite is a good water soluble source of singlet oxygen and is 1.4 times more stable than ozonide (160) <75JOCll85>. 

This dichotomy is quite evident in the reaction of cydooctane with nitronium trifluoroacetate. The products obtained were cyclooctyl triflu-oroacetate, cyclooctyl nitrate and nitrocydooctane. Conversion of adaman-tane to 1-fluoroadamantane in 95% 3ueld on reaction with nitronium tetrafluoroborate in pyridine polyhydrogen fluoride indicates that formation of adamantyl cation by formal hydride abstraction is a significant alternative to the nitration-protodenitration pathway. 

Alkyl halides, excepting alkyl fluorides, can be reduced under electrochemical conditions in aprotic solvents. For example, 1-adamantyl bromide can be reduced to... 

Reactions with Carbonyl Compounds. TMSCF3 reacts with aldehydes in the presence of a catalytic amount of tetra-w-butylammonium fluoride (TBAF) in THF to form the corresponding trifluoromethylated carbinols in good to excellent yields following aqueous hydrolysis of the silyl ethers (eq 3) 2.3.6,10 The reaction also works very well for ketones under the same conditions, with the exception of extremely hindered ones such as l,7,7-trimethylbicyclo[2.2.1]heptan-2-one, di-l-adamantyl ketone, and fenchone. The reaction has been characterized as a fluorideinduced autocatalytic reaction. Other initiators such as tris(dimethylamino)sulfonium difluorotrimethylsilicate (TASF), potassium fluoride, Ph3SnF2, andRO can also be used for these reactions. ForthereactionsofTMSCFs and perfluorinated ketones and pentafluorobenzaldehyde, excess of KF is needed. 

Preparation of Carbocations, Onium Ions, and Their Salts. SbFs is a preferred medium for the preparation of carbocations and onium ions. In fact, the first observation of stable carbocations was achieved in this medium. - By dissolving /-butyl fluoride in an excess of SbFs, the /-butyl cation was obtained (eq 26). Subsequently, many alkyl cations have been obtained in SbFs (either neat or diluted with SO2, SO2CIF, or SO2F2). The 2-norbomyl cation, one of the most controversial ions in the history of physical organic chemistry, was prepared from exo-2-fluoronorbomane in SbFs/S02 (or SO2CIF) solution (eq 27). Bridgehead cations such as 1-adamantyl, 1-trishomobarrelyl, and 1-trishomobullvalyl cations have also been similarly prepared with the use of SbFs. ... 

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