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With boranes

The desired pyridylamine was obtained in 69 % overall yield by monomethylation of 2-(aminomethyl)pyridine following a literature procedure (Scheme 4.14). First amine 4.48 was converted into formamide 4.49, through reaction with the in situ prepared mixed anhydride of acetic acid and formic acid. Reduction of 4.49 with borane dimethyl sulfide complex produced diamine 4.50. This compound could be used successfully in the Mannich reaction with 4.39, affording crude 4.51 in 92 % yield (Scheme 4.15). Analogous to 4.44, 4.51 also coordinates to copper(II) in water, as indicated by a shift of the UV-absorption maximum from 296 nm to 308 nm. [Pg.116]

C = C triple bonds are hydrated to yield carbonyl groups in the presence of mercury (II) ions (see pp. 52, 57) or by successive treatment with boranes and H2O2. The first procedure gives preferentially the most highly substituted ketone, the latter the complementary compound with high selectivity (T.W. Gibson, 1969). [Pg.131]

A number of less hindered monoalkylboranes is available by indirect methods, eg, by treatment of a thexylborane—amine complex with an olefin (69), the reduction of monohalogenoboranes or esters of boronic acids with metal hydrides (70—72), the redistribution of dialkylboranes with borane (64) or the displacement of an alkene from a dialkylborane by the addition of a tertiary amine (73). To avoid redistribution, monoalkylboranes are best used /V situ or freshly prepared. However, they can be stored as monoalkylborohydrides or complexes with tertiary amines. The free monoalkylboranes can be hberated from these derivatives when required (69,74—76). Methylborane, a remarkably unhindered monoalkylborane, exhibits extraordinary hydroboration characteristics. It hydroborates hindered and even unhindered olefins to give sequentially alkylmethyl- and dialkylmethylboranes (77—80). [Pg.310]

Primary dialkylboranes react readily with most alkenes at ambient temperatures and dihydroborate terminal acetylenes. However, these unhindered dialkylboranes exist in equiUbtium with mono- and ttialkylboranes and cannot be prepared in a state of high purity by the reaction of two equivalents of an alkene with borane (35—38). Nevertheless, such mixtures can be used for hydroboration if the products are acceptable for further transformations or can be separated (90). When pure primary dialkylboranes are required they are best prepared by the reduction of dialkylhalogenoboranes with metal hydrides (91—93). To avoid redistribution they must be used immediately or be stabilized as amine complexes or converted into dialkylborohydtides. [Pg.310]

Borabicyclo [3.3.1] nonane [280-64-8], 9-BBN (13) is the most versatile hydroborating agent among dialkylboranes. It is commercially available or can be conveniendy prepared by the hydroboration of 1,5-cyclooctadiene with borane, followed by thermal isomerization of the mixture of isomeric bicychc boranes initially formed (57,109). [Pg.310]

Several oxygen- and sulfur-substituted boranes have been reported (125—130). 1,3,2-Benzodioxaborole [274-07-7] (catecholborane, CB) (15) is the one best studied. It is commercially available or can be prepared by the reaction of catechol with borane-THF (57,131), or by other procedures (132). The product is a Hquid existing as a monomer, remarkably stable to disproportionation. No... [Pg.311]

Among chiral dialkylboranes, diisopinocampheylborane (8) is the most important and best-studied asymmetric hydroborating agent. It is obtained in both enantiomeric forms from naturally occurring a-pinene. Several procedures for its synthesis have been developed (151—153). The most convenient one, providing product of essentially 100% ee, involves the hydroboration of a-pinene with borane—dimethyl sulfide in tetrahydrofuran (154). Other chiral dialkylboranes derived from terpenes, eg, 2- and 3-carene (155), limonene (156), and longifolene (157,158), can also be prepared by controlled hydroboration. A more tedious approach to chiral dialkylboranes is based on the resolution of racemates. /n j -2,5-Dimethylborolane, which shows excellent enantioselectivity in the hydroboration of all principal classes of prochiral alkenes except 1,1-disubstituted terminal double bonds, has been... [Pg.311]

Except for a more detailed consideration of the interaction of donor ligands with boranes is beyond the scope of this review. Decaborane is... [Pg.236]

Strategy What is an immediate precursor of a primary alcohol " Perhaps a terminal alkene, which could be hydrated with non-Markovnikov regiochemistiy by reaction with borane Followed by oxidation with H2O2-... [Pg.277]

Scheme 4 outlines the synthesis of key intermediate 7 in its correct absolute stereochemical form from readily available (S)-(-)-malic acid (15). Simultaneous protection of the contiguous carboxyl and secondary hydroxyl groups in the form of an acetonide proceeds smoothly with 2,2 -dimethoxypropane and para-toluene-sulfonic acid and provides intermediate 26 as a crystalline solid in 75-85 % yield. Chemoselective reduction of the terminal carboxyl group in 26 with borane-tetrahydrofuran complex (B H3 THF) affords a primary hydroxyl group that attacks the proximal carbonyl group, upon acidification, to give a hydroxybutyrolactone. Treat-... [Pg.237]

The oxazaborolidines are easily prepared by heating ephedrine with borane dimethyl sulfide or the appropriate boronate ester. The aluminum reagent C is obtained by mixing ephedrine and trimethylaluminum. Borolidinc A is superior to its methyl derivative B and to the aluminum analog C. The diastereomeric borolidine obtained from borane and (S,S)-pseu-doephedrine failed to show any cnantioselectivity25. A variety of aromatic aldehydes can be enantioselectively alkylated in the presence of A, however, with heptanal the enantioselectivity is poor25. [Pg.177]

To conclude, we shall mention some metal-atom reactions with boranes (172) and carboranes (173). When cobalt atoms reacted with pentaboraneO) and cyclopentadiene, a number of new metalloborane clusters were formed (172), two of which were 65115003(17-05115)3 and cyclopentyl-B5H40o2(i7-05H5)3. Possible structures for the former are shown in Fig. 42. The reaction of cyclopentadiene, pentaboraneO), and 2-butyne with cobalt atoms yielded the metallocarborane species illustrated in Fig. 43 (173). [Pg.164]

Oximes are generally reduced to amines (19-44), ° but simple reduction to give hydroxylamines can be accomplished with borane or sodium cyanoborohy-dride. ... [Pg.1203]

TABLE 19.4 The Ease of Reduction of Various Functional Groups with Borane ... [Pg.1546]

Alkylation and hydrolysis of imines alkylation of aldehydes 10-107 Alkylation and hydrolysis of dithianes 10-108 Alkylation and hydrolysis of oxazines and similar compounds 10-109 Reaction of diazo aldehydes with boranes... [Pg.1644]

Reaction of halo esters or diazo esters with boranes... [Pg.1662]

Reaction of halo ketones or diazo ketones with boranes 10-112 Carbonylation of alkyl halides... [Pg.1678]

Reaction of halo sulfonic acid esters with boranes 10-125 Alcoholysis of sulfonic acid derivatives 13-15 Vicarious substitution of aryl nitro compounds... [Pg.1687]


See other pages where With boranes is mentioned: [Pg.67]    [Pg.308]    [Pg.310]    [Pg.311]    [Pg.313]    [Pg.246]    [Pg.268]    [Pg.30]    [Pg.138]    [Pg.1284]    [Pg.1290]    [Pg.172]    [Pg.321]    [Pg.532]    [Pg.533]    [Pg.861]    [Pg.941]    [Pg.1012]    [Pg.1013]    [Pg.1268]    [Pg.1592]    [Pg.1592]    [Pg.1687]    [Pg.1687]   
See also in sourсe #XX -- [ Pg.301 ]




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1,5-Cyclooctadiene, reaction with boranes

1,5-cyclooctadiene reaction with borane

2-methyl-2-butene. reaction with borane

2.3- dimethyl-2-butene, reaction with borane

Acetylene, reaction with borane

Acids reaction with boranes

Acrolein, reaction with borane

Acrolein, reaction with boranes

Aldehydes with alpine-borane

Aldehydes with deuterated alpine-borane

Aldehydes with propargylic boranes

Aldehydes, conjugated reaction with borane

Aldehydes, conjugated reaction with boranes

Aldehydes, reaction with borane enolates

Alkene reaction with borane

Alkenes alcohols with borane

Alkenes reaction with borane, isomerization

Alkenes reaction with boranes

Alkenes with borane

Alkenes with boranes

Alkynes elimination with boranes

Alkynes reaction with boranes

Allyl borane, reaction with aldehyde

Alpine borane reaction with aldehydes

Amides with borane

Amine borane, hydrogenation with

Amines with borane

Ammonia borane, reduction with

Anhydride, trifluoroacetic reaction with boranes

Asymmetric Hydroborations with Chiral Boranes

Azides reaction with boranes

B clusters in solids connections with molecular boranes

Borane , compounds with

Borane , compounds with chlorodiethoxy

Borane , compounds with derivatives

Borane , compounds with dichloroethoxy

Borane , compounds with dimeric

Borane , compounds with dimeric derivatives

Borane carbonyls reactions with

Borane catechol, reaction with

Borane complex with dimethyl sulfide

Borane complexes reaction with

Borane complexes reaction with alkynes

Borane dative bond with

Borane enantioselective allylation with

Borane hydration of alkenes enantioselective allylation with

Borane hydroboration with

Borane reacting with

Borane reaction with 3-hexyne

Borane reaction with alkynes

Borane reaction with boron trichloride

Borane reaction with halo carbonyls

Borane reactions with aldehydes

Borane reactions with benzaldehyde

Borane reagent formed with 2-aminoethanol

Borane with benzyl bromide

Borane, allyldiisopinocampheylreactions with aldehydes

Borane, allyldiisopinocampheylreactions with aldehydes asymmetric synthesis

Borane, allyldimesitylreactions with lithium amides

Borane, allyldimethoxyreactions with aldimines

Borane, allylreaction with imines

Borane, carboxy-compd. with trimethylamine

Borane, chloro-, compound with ethyl ether

Borane, compd. with thiobis[methane

Borane, crotyldiisopinocampheylboratropic shift reactions with aldehydes

Borane, crotylreactions with imines

Borane, crotylreactions with imines synthesis

Borane, derivatives addition reactions with aldehydes

Borane, dialkylcrotylisomerization reactions with carbonyl compounds

Borane, dimesitylmethylreactions with bases

Borane, diphenylhydroxyreaction with ethoxyacetylene

Borane, diphenylhydroxyreaction with ethoxyacetylene mercury acetate

Borane, electrophilicity reaction with alkenes

Borane, electrophilicity reaction with alkynes

Borane, electrophilicity reaction with carboxylic acids

Borane, triethylreaction with thioallyl anions

Borane, triethylreaction with thioallyl anions a-selectivity

Borane, with

Borane, with

Borane, with silyl-alkynes

Borane-tetrahydrofuran, reaction with

Boranes adducts with amines

Boranes alkynyl, reactions with aldehydes and ketones

Boranes amine, hydrogenation with

Boranes chloride, reaction with alkynes

Boranes cyclic, coupling with

Boranes equilibrium with diboranes

Boranes ethylene derivatives with

Boranes hydrogenations with

Boranes oxidation with NaOH

Boranes palladium-catalyzed coupling with halides

Boranes radical reactions with

Boranes reaction with

Boranes reaction with alkenes, regioselectivity

Boranes reaction with aminals

Boranes reaction with basic hydrogen peroxide

Boranes reaction with carbon

Boranes reaction with carbon dioxide

Boranes reaction with carboxylic acids

Boranes reaction with chloramine

Boranes reaction with diazo compounds

Boranes reaction with epoxides

Boranes reaction with halo carbonyl compounds

Boranes reaction with halogen

Boranes reaction with hydroperoxide anion

Boranes reactions with aldehydes

Boranes reactions with aldehydes and ketones

Boranes syntheses with

Boranes vinyl, reaction with carboxylic acids

Boranes with Two Boron-Bonded Nitrogen Atoms

Boranes with acetylides

Boranes with alkynes

Boranes with amides

Boranes with aryl halides

Boranes with diazo compounds

Boranes with halogens

Boranes with oxygen

Boranes, alkenyldialkylbrominolysis reaction with iodine

Boranes, alkenyloxyreactions with ketones

Boranes, alkenyloxyreactions with ketones synthesis

Boranes, alkenyloxyreactions with ketones via acylation of boron-stabilized carbanions

Boranes, alkoxyreaction with organometallic compounds

Boranes, alkoxyreaction with organometallic compounds formation of aldehydes

Boranes, alkyl reaction with aldehydes

Boranes, alkyldimesitylreactions with bases

Boranes, chlororeaction with acetophenone

Boranes, dialkylallylreaction with ethoxyacetylene

Boranes, elimination with alkenes

Boranes, oxidation with

Boranes, reaction with bromo esters

Boranes, reaction with chromic acid

Boranes, reaction with disulfides

Boranes, reaction with halo-derivatives

Boranes, reaction with heterocycles

Boranes, reaction with hydride

Boranes, reaction with ketenes

Boranes, reaction with oxygen

Boranes, vinylreactions with organometallic compounds

Boranes, vinylreactions with organometallic compounds synthesis

Boranes, vinylreactions with organometallic compounds via hydroboration of 1-alkynes

Boranes, with alkynes, reduction

Boranes, with alkynes, reduction acids

Boranes, with alkynes, reduction peroxide

Boranes, with metal alkyne

Boron boranes with dimethylsulfide

Bromo ketones, reaction with boranes

Carbon monoxide reaction with boranes

Carbon monoxide with boranes

Carboxylic acid reaction with borane

Carboxylic acids reduction with borane

Carboxylic acids with boranes

Cis/trans-Selective reactions with boranes

Complexes with Borane

Conjugated compounds, reaction with boranes

Conjugated dienes, reaction with borane

Copolymerization olefins, with borane monomers

Diazo compounds, alkylation with boranes

Diazo esters with boranes

Diazo ketones with boranes

Diazo reaction with boranes

Diazoketones reaction with boranes

Diborane equilibrium with borane

Dienes reaction with boranes

Diols reaction with boranes

Enantioselectivity, with Alpine borane

Enantioselectivity, with chiral boranes

Esters with boranes

Ethylenediamine borane reductions with

Exchange with boranes

Furan, tetrahydro-, compound with borane

Halo esters reaction with boranes

Halo ketones with boranes

Hydroboration with chiral boranes

Hydroperoxide anions reaction with borane

Ketone with neat Alpine-Borane

Ketones asymmetric reduction with Alpine-borane

Ketones reduction with boranes

Ketones with Alpine-Borane

Ketones with borane

Ketones, conjugated reaction with borane

Ketones, conjugated reaction with boranes

Ketones, reaction with Alpine borane

Ketones, reaction with boranes

Lactams reduction with borane

Lewis bases, complexes with borane

Malic acid reduction with borane

Methyl sulfide, compd. with borane

Nitriles, reaction with borane

Oxazaborolidine, complex with borane

Oxirane reactions with borane

Peroxides hydrogen peroxide reaction with boranes

Pyridine complex with borane

Pyridines reactions with boranes

Reaction with borane

Reduction Reaction with Borane

Reduction of ketones with borane

Reduction reactions with boranes

Reduction with borane

Reduction with boranes

Regioselectivity alkene reaction with borane

Sodium reaction with boranes

Sulfides reaction with boranes

Tetrahydrofuran complex with borane

Tetrahydrofuran complexed with borane

Thexyl borane hydroboration with

Titanium complexes with boranes

Trimethylamine, complex with borane

Unsaturated aldehydes with boranes

Unsaturated ketones with boranes

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