Adamantane arylation

Haloalkynes (R—C=C—X) react with ArSnBu3 and Cul to give R—C= C—Ar. Acetylene reacts with two equivalents of iodobenzene, in the presence of a palladium catalyst and Cul, to give 1,2-diphenylethyne. 1-Trialkylsilyl alkynes react with 1-haloalkynes, in the presence of a CuCl catalyst, to give diynes and with aryl triflates to give 1-aryl alkynes. Alkynes couple with alkyl halides in the presence of Sml2/Sm. Alkynes react with hypervalent iodine compounds " and with reactive alkanes such as adamantane in the presence of AIBN. ... 

The third arrangement (ee, 205) is of particular interest because considerable ICSs were reported (indicating intramolecular through-bond interactions) when the substituents had lone electron pairs available. Again adamantanes, such as 207 to 209, served as model compounds in systematic studies (176,218,232). Whereas Lippmaa and co-workers (176) found noticeable ICSs in their derivatives of 207 (X, Y = OH, Br, aryl, COOH, CH2COOH, CH2Br) only for the... 

Highly enantioselective intermolecular C-H insertion into cyclohexane and cyclopentane is possible using the Rh2(S-DOSP)4 carbenoids generated from aryl diazoacetates 172 to form 173 (Eq. 21) [121, 130]. The enantioselectivity is enhanced when the reactions are conducted at lower temperatures, without any deleterious effect on the catalytic activity or product yield [130]. Extending the reaction to other cyclic and acyclic hydrocarbons has revealed a dehcate balance required between the steric environment and the electronic state of the carbon undergoing C-H insertion [130]. The decreasing enantioselectivity and yield of C-H insertion into adamantane 174 (67% yield, 90% ee). 

Ifenprodil (= l-Methyl-2-hydroxy-2-(4-hydroxyphenyl) ethyl-1 -(4-benzyl-piperidine)] -(aryl piperidine) [at(/o-3-(Indol-2-yl)-8-methyl-8-azabicyclo-[3.2.1] octane] (indolotropane) [Kynurenic acid (= 4-Hydroxy-2-quinolinecarboxylic acid)] (quinoline carboxylic acid) [Memantine (= 1-Amino-3,5 dimethyladamantane)] (amino adamantane, amino cyclic aliphatic) [Methadone (= 6-Dimethylamino-4,4-diphenyl-3-heptanone)] (aryl tertiary amine) [em/o-3-(l -Methylindol-2-yl)-8-methyl-8-azabicyclo-[3.2.1] octane(indolotropane) exo- 3-( 1 -Methylindol-2-yl)-8-methyl-8-... 

As a rather special case, alkyl aldehydes are reduced with titanocen dichloride to the hydrocarbons through a titanium-bonded alkenic intermediate as shown by a deuterium-labeling experiment. Thus, dodecanal was converted to dodecane in 71% yield, along with dodecan-I-ol in 15-20% yield alkyl ketones such as adamantan-2-one and dodecan-6-one afforded alcohols as the major products. No reduction occurred in the case of aryl aldehydes where alkene formation is impossible. ... 

X-Ray structure analysis of 14a, 15a, and 15b has established the central adamantane cage which is characteristic of the unsolvated triamides [6, 8], Whereas there is little appreciable interaction between the periphery of the molecules in the structures of the t-butyl substituted species 15a and 15b, the two-coordinate Li-atoms are "internally solvated" by the phenyl groups in the chiral triamide 14a (Fig. 3). The orientation of the aryl rings towards the puckered six-membered (LiN)s-ring and the short contact between Li and C7 indicates a direct interaction between the metal atoms and the periphery. 

Laszlo and coworkers achieved the direct arylation of adamantane by employing FeCb-doped KIO montmorillonite (equation 93). Depending upon Ae amounts of adamantane, FeCb, the catalyst and the reaction time, varying proportions of mono- and di-arylated adamantanes were obtained. The results were taken to support the intermediacy of a 1-adamantyl cation. 

Tseng, C.C., Handa, I., Abdel-Sayed, A.N.. and Bauer, L., V-[(Aryl substituted adamantane)alkyl]-2-mercaptoacetamidines, their corresponding disulfides and 5-phosphorothioates, Tetrahedron, 44, 1893, 1988. 

Steric factors also have an influence on cyclotrimerization. Very bulky ori/io-substituted aryl cyanides require in some cases more vigorous reaction conditions compared to meta- and para-derivatives and the yields are lower. Anthracene-9-carbonitrile, adamantane-1-carboni-trile, and phenanthrene-9-carbonitrile do not undergo trimerization, even under 8000-17000atm at 150-240 °C.141... 

The same authors reported the use ofa phospha-adamantane as a suitable ligand for catalytic aminations [116]. This ligand was found useful for the aminations of aryl iodides, bromides and chlorides in high yields, using NaOt-Bu as base. The ligand is crystalline, air-stable and can be recovered using chromatographic procedures. 

After a preliminary report [129], in 2006, Adjabeng etal. [130] reported the synthesis and application of novel phospa-adamantane ligands for the Pd-catalyzed Suzuki-Miyaura reaction. These compounds were originally reported by Epstein and Buckler in 1961 [132]. In this procedure, the phenyl derivative - l,3,5,7-tetramethyl-2,4,8-trioxa-6-phenyl-6-phospha-adamantane (Figure 1.40b) - was used in the arylation of aryl iodides, bromides, and activated chlorides with a variety of boronic acids at room temperature in a few hours with high yields. The ligand is comparable to P(fBu)j [126] with... 

The method involves calculating the accessible space outside the van der Waals radii above and below the carbonyl- (or other n-) plane. The stereoselectivity is then predicted from the difference between the -plane-divided accessible space on each side. Several hydride reductions of cyclohex- and cyclohept-anones and of adamantan-2-ones have been used to exempUty the method, which does not require consideration of transition-state effects. For 5-substituted adamantan-2-ones (52), 7T-facial stereoselection is found to arise mainly trom steric effects in most cases, except for aryl substituents, where orbital control appears dominant. In assessing the steric, electronic, and orbital contributions to r-facial stereoselectivity in nucleophilic addition to bicyclo[2.2.1]heptan-7-ones (53), the results are compared with Mehta s experimental data for the system. - In the case of nucleophilic additions to... 

The first report" of an intermolecular amino-alkylation has been published with the synthesis of 3-aryl-4-azidohomo-adamantane (220). The reaction occurs in yields in excess of 90%, presumably via an imine intermediate, and does not proceed without AICI3. 

Cul-catalyzed coupling reactions. An example is shown in Scheme 3.31, the synthesis of aryl azide 223 from L-phenylalanine-derived iodide 222 in 91% yield. A similar approach allows the synthesis of stable organic polyazides, based on methane and adamantane cores 225. Despite the high energetic properties, these rigid structures can be handled without special precautions. ... 

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