Phase transfer Pd(0) catalyzed polymerization reactions. III. Polymerization by cross-coupling of alkyl–boron compounds and aromatic halides catalyzed by PdCl2 (dppf) and bases

This paper describes a novel polymerization reaction which consists of a sequence of hydroboration of a diolefin with 9-borabicyclo[3.3.1]nonane (9-BBN) followed by the intermolecular cross-coupling of the resulting 1,1′-bis(B-alkanediyl-9-borabicyclo[3.3.1]nonanes with dihaloarenes. The reaction is performed in the presence of dichloro[1,1′-bis(diphenylphosphino)ferrocene] palladium (II) [PdCl₂ (dppf)], a base, and a phase transfer catalyst. Both steps are performed in the same reaction flask. Alternatively, this polymerization reaction can be applied to bifunctional monomers containing an olefin and a haloarene group, for example, p-bromostyrene.     

Conformational analysis of 3-borabicyclo[3.3.1]nonane derivatives

Conformations of 3-borabicyclo[3.3.1]nonane derivatives have been studied by means of ¹H and ¹³C NMR spectroscopy. With the aid of the coupling constants ³J(HH) and ¹³C chemical shifts it has been shown that all the derivatives of 3-borabicyclo[3.3.1]nonane with the trigonal boron atom studied are in a flattened double-chair conformation. In 3-borabicyclo[3.3.1]nonane derivatives with the tetra-coordinated boron atom and substituents at the 7α-position, the chair-boat conformation predominates, the boat conformation being characteristic of the cyclohexane ring; exceptions are the compounds with the internal donor—acceptor bond between the boron atom an 7α-substituent.     

Synthesis of 6,7-benzo-3-borabicyclo[3.3.1]nonane and its 3-aza analog from 2-allylphenyl(diallyl)borane. Intramolecular arylboration of the C=C bond

A method was developed for the synthesis of 6,7-benzo-3-borabicyclo[3.3.1]nonane and 6,7-benzo-3-azabicyclo[3.3.1]nonane derivatives based on intramolecular cyclization of 2-allylphenyl(diallyl)borane. Intramolecular arylboration of the double bond in 1,5-diallyl-2,3-benzo-1-boracyclohexane was carried out for the first time. Conventional oxidation (H₂O₂-OH⁻) of 6,7-benzo-3-methoxy-3-borabicyclo[3.3.1]nonane afforded cis-1,3-di(hydroxymethyl) tetralin. The structure of the latter was established by X-ray diffraction analysis.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 668–672, March, 2005.     

One-pot conversion of carboxylic acids to aldehydes through treatment of acyloxy-9-borabicyclo[3.3.1]nonanes with lithium 9-boratabicyclo[3.3.1]nonane

Carboxylic acids are readily reduced to the corresponding aldehydes in high yields by treatment of acyloxy-9-borabicyclo[3.3.1]nonanes with lithium 9-boratabicyclo[3.3.1]nonane (Li 9-BBNH) at room temperature.     

Organoboron compounds : CCCXCIX. The matteson-pasto rearrangement in the series of 3-borabicyclo[3.3.1]nonane compounds

Bromination of 3-isopropyl-7-methyl- and 3-isopropyl-7-bromomethyl-3-borabicyclo[3.3.1]nonane leads to corresponding 3-(2-bromo-2-propyl) derivatives, which, on treatment with alcohols or pyridine as well as on heating, undergo the Matteson-Pasto rearrangement to convert into 3-X-4,4,8-trimethyl- and 3-X-4,4-dimethyl-8-bromomethyl-3-borabicyclo[4.3.1]decane (X = Br, OR). Interaction between triethylamine and 3-(2-bromo-2-propyl)-7-methyl-3-borabicyclo[3.3.1]nonane is accompanied by dehydrobromination leading to 3-isopropenyl-7-methyl-3-borabicyclo[3.3.1]nonane. Carbonylation of 3,4,4,8-tetramethyl-3-borabicyclo[4.3.1]decane at 140°C is accompanied by migration of two alkyl groups from the boron to the carbon atom, and subsequent oxidation with H₂O₂ produces 1-(2-hydroxy-2-methyl-1-propyl)-3-acetonyl-5-methyl-cyclohexane. Under more forcing conditions (180-195°C), the third alkyl group also migrates to give, after oxidation, a mixture of isomeric 3,4,4,8-tetramethylbicyclo[4.3.1]decan-3-ols. 3-n-Butoxy-4,4-dimethyl-8-bromomethyl-3-borabicyclo[4.3.1]decane, on treatment with Lì, undergoes cyclization to afford 4,4-dimethyl-3-borahomoadamantane, carbonylation and subsequent oxidation of which gave 4,4-dimethylhomoadamantan-3-ol.     

Pincer-Supported Gallium Complexes for the Catalytic Hydroboration of Aldehydes,Ketones and Carbon Dioxide

Gallium hydrides stabilised by primary and secondary amines are scarce due to their propensity to eliminate dihydrogen. Consequently, their reactivity has received limited attention. The synthesis of two novel gallium hydride complexes HGa(THF)[ON(H)O] and H₂Ga[μ²-ON(H)O]Ga[ON(H)O] ([ON(H)O]²⁻=N,N-bis(3,5-di-tert-butyl-2-phenoxy)amine) is described and their reactivity towards aldehydes and ketones is explored. These reactions afford alkoxide-bridged dimers through 1,2-hydrogallation reactions. The gallium hydrides can be regenerated through Ga−O/B−H metathesis from the reaction of such dimers with pinacol borane (HBpin) or 9-borabicyclo[3.3.1]nonane (9-BBN). These observations allowed us to target the catalytic reduction of carbonyl substrates (aldehydes, ketones and carbon dioxide) with low catalyst loadings at room temperature.     

Total Synthesis of (±)-Zearalanone

Summary.  A new approach to the macrocyclic lactone zearalanone is described utilizing an alkenol and an arene trifluoromethanesulfonate as starting materials. The key step is a Pd(0)-catalyzed cross-coupling of the arene trifluoromethanesulfonate with a 9-alkyl-9-borabicyclo[3.3.1]nonane derived from the alkenol. The title compound is obtained by macrolactonization of a hydroxy acid under Mitsunobu conditions. Received December 29, 2000. Accepted February 5, 2001     

Facile and convenient synthesis of B-amino-9-borabicyclo[3.3.1]nonanes. Aminoboration of lsocyanates

The reaction of 9-borabicyclo[3.3.1]nonane (9-BBN) with aliphatic and aromatic primary and secondary amines in tetrahydrofuran (THF) at 65°C proceeds rapidly and quantitatively with evolution of hydrogen and the formation of the corresponding B-amino-9-borabicyclo[3.3.1] nonane (B-amino-9-BBN). Simple evaporation of THF from the reaction mixture gives the B-amino-9-BBN derivatives in high yield and purity. These B-amino-9-BBN derivatives are reactive towards alkyl and aryl isocyanates. Consequently, the aminoboration of various isocyanates has been studied using B-phenylamino-9-BBN. Thus, two equivalents of isocyanates react with one equivalent of B-phenylamino-9-BBN to afford, following the hydrolysis of the intermediate with ethanolamine, N, N'-disubstituted-N -(phenylamido)-ureas in excellent yields. A plausible mechanism for this aminoboration reaction of isocyanates is also presented.     

B-bromo-9-borabicyclo[3.3.1]nonane. A convenient and selective reagent for ether cleavage

In methylene chloride solution, B-bromo-9-borabicyclo[3.3.1]nonane (BBr-9-BBN) readily cleaves, in excellent yield, a variety of ethers of representative structural types. The reagent can also be used for selective cleavage of one of the ether groups in a molecule containing more than one such group.     

Organoboron compounds

Conclusions Some B-derivatives (alkoxy, alkylmercapto, amino) of 3-borabicyclo[3.3.1]-6-nonene and 3-borabicyclo[3.3.1]nonane were obtained and studied.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, N. 4, pp. 824–827, April, 1968.     

An Aldol Reaction of Boron Enolates Generated by the 1,4-Addition of B-Br-9-BBN to α, β-Unsaturated Ketones. A Synthesis of α-Bromomethyl-α, β-Unsaturated Ketones

α-Bromomethyl-α,β-unsaturated ketones can be prepared easily by the successive addition of α,β-unsaturated ketones and then aldehydes to B-bromo-9-borabicyclo[3.3.1]nonane.     

Use of enyne compounds in the synthesis of insect pheromones

A new approach has been developed to the synthesis of monogenic insect pheromones with acetogenin and macrolide structures, using the low reactivity of ozone and of 9-borabicyclo[3.3.1]nonane towards an acetylenic function as compared with a vinyl function.Institute of Organic Chemistry, Ufa Scientific Center of the Russian Academy of Sciences. Translated from Khimiya Prirodnykh Soedinenii, Vol. 33, No. 1, pp. 34–41, January–February, 1997.     

Synthèse de spirohydantoines dérivées du diphényl-2,4-aza-3-bicyclo-[3.3.1]nonane et du diphényl-7,9-aza-8-bicyclo[4.3.1]decane par réaction de Bucherer dans la N,N-diméthylformamide: Influence de la température et cours stéréochimique. Communication préliminaire

Synthesis of Spyrohydantoines Derivatives of 2,4-Diphenyl-3-azabicyclo[3.3.1]nonane and 7,9-Diphenyl-8-azabicyclo[4.3.1]decane via Bucherer Reaction in N,N-Dimethylformamide: Influence of the Temperature and Stereochemical Path The unreactives ketones related to 2,4-diphenyl-3-azabicyclo [3.3.1]nonan-9-one to the Bucherer reaction in usuals conditions show excellent reactivity in DMF. as unique solvant. The stereochemical paths of these reactions and the synthetic utility of the temperature modification are described.     

Hydroboration of terpenes—VIII: Cyclic hydroboration of d-(+)-limonene. A stereoselective synthesis of d-(−)-(1R, 2R, 4R)-limonene-2,9-diol and d-(−)-(1R, 2R, 4R)-carvomenthol

d-(+)-Limonene can be converted into the corresponding bicyclic organoborinate intermediate, B-methoxy-4,8-dimethyl-2-borabicyclo[3.3.1]nonane, by cyclic hydroboration with borane in THF, followed by methanolysis, and distillation of the product. Alternatively, cyclic hydroboration of d-(+)-limonene with thexylborane provides the related bicyclic organoborane intermediate, B-thexyl-4,8-dimethyl-2-borabicyclo[3.3.1]nonane. Oxidation of the respective intermediates produces d-(?)-(1R, 2R, 4R)-limonene-2,9-diol. Protonation of the bicyclic thexyl intermediate, followed by oxidation, provides d-(?)-(1R, 2R, 4R)-carvomenthol. These results suggest that the cyclic hydroboration of dienes can provide a valuable means for controlling the exact site of hydroboration, leading to a stereoselective synthesis of alcohols.     

Substituierte 9-Oxabicyclo[4.2.1]- und 9-Oxabicyclo[3.3.1]nonane IV. endo,endo-2,5-Dihydroxy-9-oxabicyclo[4.2.1]nonan,endo, endo-, endo,exo- und exo,exo-2,6-Dihydroxy sowie endo,exo-2,7-Dihydroxy-9-oxabicyclo[3.3.1]nonan; Darstellung und Umwandlungsprodukte

The synthesis of the following compounds and reaction products thereof are described: endo, endo-2,5-dihydroxy-9-oxabicyclo[4.2.1]nonane ( 3–5 ), epimeric 2,6-dihydroxy-9-oxabicyclo[3.3.1]nonanes (endo, endo: 6–8 , exo, exo: 29–32 , and endo, exo: 43–45 ), and endo, exo 2,7-dihydroxy-9-oxabicyclo[3.3.1]nonane ( 46–50 ).     

9-BBN还原1,7-辛二烯-3-醇的研究

本文报道了用9-BBN与1,7-辛二烯-3-醇进行硼氢化反应的结果。这个反应的区域选择性极低,除生成1-辛烯-3-醇(47％)外,同时还生成了7-辛烯-3-醇(41％)和辛醇-3(12％)。     

Chemiluminescence in the interaction of organoboron peroxides with water

Chemiluminescence (CL) was detected in the reactions of organoboron peroxides, intermediate products of the oxidation of 9-borabicyclo[3.3.1]nonane (1) by water. Triplet cyclooctanone emitting at λ=420±15 nm is the emitter of CL. A mechanism for the formation of the excited ketone was suggested. The interaction of water with other components of the reaction mixture (the initial boron hydride I, end products of its oxidation, and a number of intermediate radicals) are not accompanied by CL. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1692–1695, September, 1997.     

Novel Cellulose Ethers: Synthesis and Structure Characterization of 3-Mono-O-(3′-hydroxypropyl) Cellulose

Summary: The synthesis of 3-mono-O-(3′-hydroxypropyl) cellulose via 3-mono-O-allyl-2,6-di-O-thexyldimethylsilyl cellulose was studied. Conversion of the double bond with 9-borabicyclo[3.3.1]nonane and subsequent alkaline oxidation lead to the 3′-hydroxypropyl group. Finally, the treatment with tetrabutylammonium fluoride trihydrate yields the complete cleavage of the protecting groups. The structure of the polymer was confirmed by one- and two dimensional NMR spectroscopic techniques. 3-mono-O-(3′-hydroxypropyl) cellulose is soluble in water and aprotic-dipolar organic media.     

A practical large scale chemical synthesis of chiral glycines

(R)- and (S)-[2-²H]glycine of high chiral purity were synthesized in large quantities in ≈ 40% overall yield from readily available starting materials via a totally chemical procedure. Reduction of either [1-²H]-furfural or [1-²H]-4-methoxybenzaldehyde with either (+) or (-)-B-isopinocampheyl-9-borabicyclo[3.3.1]nonane gave chiral arylmethyl alcohols which were converted into their respective phthaloyl amino derivatives of the opposite configuration at the methylene carbon via the Mitsunobu reaction. The aromatic groups were oxidatively unmasked to give their corresponding glycine derivatives by either ozone or ruthenium tetraoxide oxidation.     

Allylboranes and the synthesis of diamond molecules

The review summarizes our data on the synthesis of selected allylic, bicyclic, and highly strained cage boranes, investigations of their physicochemical properties, and applications of these compounds. Procedures for the construction of boron polyhedral systems, transformations of 1-boraadamantane compounds into 1-hydroxyadamantanes and 1-azaadamantanes, and the synthesis of chiral derivatives of 1-boraadamantane and 3-borabicyclo[3.3.1]nonane are considered. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 788–800, April, 2008.