106-24-1

Basic information

• Product Name: Geraniol
• Synonyms: 3,7-Dimethyl-trans-2, 6-octadien-1-ol;2,6-Dimethyl-trans-2, 6-octadien-8-ol;trans-Geraniol;Geraniol alcohol;Guaniol;(E)-3,7-dimethylocta-2,6-dien-1-ol;Lemonol;2,6-Octadien-1-ol,3,7-dimethyl-,(2E)-;Geranyl alcohol;Geraniol extra;trans-3,7-Dimethyl-2,6-octadien-1-ol;Nerol;Geraniol;2,6-Dimethyl-2,6-octadien-8-ol
• CAS NO: 106-24-1
• Molecular Formula: C₁₀H₁₈O
• Molecular Weight: 154.2493
• EINECS: 203-377-1
• Product Categories: Steroid Metabolism;Acyclic;Alkenes;Allium sativum (Garlic);Building Blocks;Cancer Research;Chemical Synthesis;Chemopreventive Agents;Citrus aurantium (Seville orange);Elettaria Cardamomum (Cardamom);Enzyme Inhibitors;Humulus lupulus (Hops);Hypericum perforatum (St John′;Lavandula angustifolia (Lavendar tea);Metabolic Pathways;Metabolomics;Nutrition Research;Ocimum basilicum (Basil);Organic Building Blocks;Phytochemicals by Plant (Food/Spice/Herb);s wort);Terpenoid Metabolism;Terpenoids;Vaccinium myrtillus (Bilberry);Acyclic Monoterpenes;Biochemistry;Terpenes;Zingiber officinale (Ginger)
• Mol File: 106-24-1.mol
• Article Data: 235

Chemical Properties

• Melting Point: -15℃
• Boiling Point: 229.499 °C at 760 mmHg
• Flash Point: 76.667 °C
• Appearance: colourless to pale yellow liquid with an odour of roses
• Density: 0.867 g/cm³
• Vapor Density: 5.31 (vs air)
• Vapor Pressure: 0.013mmHg at 25°C
• Refractive Index: 1.471
• Storage Temp.: 2-8°C
• Solubility: water: soluble0.1g/L at 25°C
• PKA: 14.45±0.10(Predicted)
• Water Solubility: PRACTICALLY INSOLUBLE
• Stability: Stable. Combustible. Incompatible with strong oxidizing agents.
• Merck: 14,4403
• BRN: 1722456
• CAS DataBase Reference: Geraniol(CAS DataBase Reference)
• NIST Chemistry Reference: Geraniol(106-24-1)
• EPA Substance Registry System: Geraniol(106-24-1)

Safety Data

• Hazard Codes: Xi:Irritant
• Statements: R36/37/38:
• Safety Statements: S24/25:
• RIDADR: UN1230 - class 3 - PG 2 - Methanol, solution
• WGK Germany: 1
• RTECS: RG5830000
• TSCA: Yes
• Hazardous Substances Data: 106-24-1(Hazardous Substances Data)

Usage

Description

Different sources of media describe the Description of 106-24-1 differently. You can refer to the following data:
1. Geraniol is a kind of monoterpenoid as well as alcohol. It is mainly existed in plant oils such as rose oil, palmarosa oil, and citronella oil. It can also be found in plants such as geraniums and lemongrass. It has a rose-like scent and is therefore used in perfumes as well as many kinds of flavors such as peach, raspberry, grapefruit, red apple, plum, lime, orange, lemon, and blueberry. Another major application of geraniol is being used as an effective plant-based insect repellent for treatment of mosquitoes, house flies, stable flies, cockroaches, fire ants, fleas and lone star ticks. On the other hand, its scent can also attract bees.
2. Geraniol has a characteristic rose-like odor. Geraniol may be prepared by fractional distillation from those essential oils rich in geraniol, or synthetically from myrcene; commercial geraniol cannot be classified according to its alcohol content, as most of the recurring impurities are alcoholic in nature (nerol, citronellol, tetrahydrogeraniol). Gas-chromatography techniques may be usefully employed to determine the geraniol content in a product.

References

https://en.wikipedia.org/wiki/Geraniol https://pubchem.ncbi.nlm.nih.gov/compound/geraniol#section=Top

Chemical Properties

Different sources of media describe the Chemical Properties of 106-24-1 differently. You can refer to the following data:
1. Geraniol has a characteristic rose-like odor The physical constants vary for the various commercial products, depending on the total geraniol content; specifc gravity and refractive index may be indicative of the purity of the product Commercial geraniol cannot be classifed according to its alcohol content, as most of the recurring impurities are alcoholic in nature (nerol, citronellol, tetrahydrogeraniol) Gas chromatography techniques may be usefully employed to determine the gera- niol content in a product.
2. Geraniol occurs in nearly all terpene-containing essential oils, frequently as an ester. Palmarosa oil contains 70–85% geraniol; geranium oils and rose oils also contain large quantities. Geraniol is a colorless liquid, with a floral, rose-like odor. Since geraniol is an acyclic, doubly unsaturated alcohol, it can undergo a number of reactions, such as rearrangement and cyclization. Rearrangement in the presence of copper catalysts yields citronellal. In the presence of mineral acids, it cyclizes to form monocyclic terpene hydrocarbons, cyclogeraniol being obtained if the hydroxy function is protected. Partial hydrogenation leads to citronellol, and complete hydrogenation of the double bonds yields 3,7-dimethyloctan-l-ol (tetrahydrogeraniol). Citral may be obtained from geraniol by oxidation or by catalytic dehydrogenation. Geranyl esters are prepared by esterification. Geraniol is one of the most frequently used terpenoid fragrance materials. It can be used in all floral, rose-like compositions and does not discolor soaps. In flavor compositions, geraniol is used in small quantities to accentuate citrus notes. It is an important intermediate in the manufacture of geranyl esters, citronellol, and citral.
3. colourless to pale yellow liquid with an odour of roses

Occurrence

The presence of geraniol in nature has been reported in more than 160 essential oils: ginger grass, lemongrass, Ceylon and Java citronella, tuberose, oak musk, orris, champaca, ylang-ylang, mace, nutmeg, sassafras, Cayenne Bois-de-Rose, Acacia farnesiana, geramium clary sage, spike, lavandin, lavender, jasmine, coriander, carrot, myrrh, eucalyptus, lime, mandarin petitgrain, bergamot petitgrain, bergamot, lemon, orange and others The essential oils of palmarosa and Cymbopogon winterianus contain the highest levels of geraniol (approx 80 to 95%) Also reported in numerous other sources including apple juice, citrus peel oils and juices, bilberry, cranberry, other berries, guava, papaya, cinnamon, ginger, corn mint oil, mustard, nutmeg, mace, milk, coffee, tea, whiskey, honey, passion fruit, plums, mushrooms, mango, starfruit, cardamom, coriander leaf and seeds, litchi, Ocimum basilicum, myrtle leaf, rosemary, clary sage, Spanish sage and chamomile oil

Uses

Different sources of media describe the Uses of 106-24-1 differently. You can refer to the following data:
1. Geraniol is used in the synthesis of insect repellant. It is also used in the synthesis of Angelicoin A and Herecinone J, which inhibit collagen-induced platelet aggregation.
2. Geraniol was used in field evaluation of synthetic herbivore-induced plant volatiles as attractants to beneficial insects.It was used to evaluate the tumor-suppressive potency of isoprenoids in vitro and in vivo.
3. geraniol is perfuming and with tonic properties. It is a primary constituent in many essential oils, including citronella, lavender, lemongrass, orange flower, and ylang-ylang.

Definition

ChEBI: A monoterpenoid consisting of two prenyl units linked head-to-tail and functionalised with a hydroxy group at its tail end.

Preparation

A convenient route for the production of geraniol and nerol consists of the hydrogenation of citral, which is used in large quantities as an intermediate in the synthesis of vitamin A. Large-scale processes have, therefore, been developed for producing geraniol. Currently, these are far more important than isolation from essential oils. Nevertheless, some geraniol is still isolated from essential oils for perfumery purposes. 1) Isolation from essential oils: Geraniol is isolated from citronella oils and from palmarosa oil. Fractional distillation of, for example, Java citronella oil (if necessary, after saponification of the esters present) yields a fraction containing about 60% geraniol, as well as citronellol and sesquiterpenes. Aproductwith a higher geraniol content and slightly different odor quality for use in fine fragrances is obtained by fractionating palmarosa oil after saponification of the geranyl esters. 2) Synthesis from β-pinene: Pyrolysis of β-pinene yields myrcene, which is converted into a mixture of predominantly geranyl, neryl, and linalyl chloride by addition of hydrogen chloride in the presence of small amounts of catalyst, for example, copper(I) chloride and an organic quaternary ammonium salt. After removal of the catalyst, the mixture is reacted with sodium acetate in the presence of a nitrogen base (e.g., triethylamine) and converted to geranyl acetate, neryl acetate, and a small amount of linalyl acetate.Geraniol is obtained after saponification and fractional distillation of the resulting alcohols. 3) Synthesis from linalool: A 96% pure synthetic geraniol prepared by isomerization of linalool has become commercially available. Orthovanadates are used as catalysts, to give a >90% yield of a geraniol–nerol mixture. Geraniol of high purity is finally obtained by fractional distillation. A considerable portion of commercially available geraniol is produced by a modified process: linalool obtained in a purity of about 65% from α-pinene is converted into linalyl borates, which rearrange in the presence of vanadates as catalysts to give geranyl and neryl borates. The alcohols are obtained by hydrolysis of the esters. 4) Synthesis from citral: Citral has very recently come to be produced petrochemically in very large quantities, so partial hydrogenation of citral has become a very economical route for the production of geraniol. A high selectivity for this reaction can be achieved by the use of special catalysts [106] or by special reaction techniques.

Aroma threshold values

Detection: 4 to 75 ppb.

Taste threshold values

Taste characteristics at 10 ppm: sweet foral rose, citrus with fruity, waxy nuances.

General Description

Colorless to pale yellow oily liquid with a sweet rose odor.

Reactivity Profile

An unsaturated aliphatic hydrocarbon and an alcohol. Flammable and/or toxic gases are generated by the combination of alcohols with alkali metals, nitrides, and strong reducing agents. They react with oxoacids and carboxylic acids to form esters plus water. Oxidizing agents convert them to aldehydes or ketones. Alcohols exhibit both weak acid and weak base behavior. They may initiate the polymerization of isocyanates and epoxides.

Flammability and Explosibility

Nonflammable

Anticancer Research

Starting from antitumor activity against several cell lines by an arrest occurring atthe G0/G1 cell cycle and ultimately with an increase of apoptosis, this molecule wasfound to interfere with the mevalonic cycle enzyme. Suppression of prenylation ofproteins leads to the inhibition of DNA synthesis, and the suppression of 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) leads to a reduction of the mevalonate pool andthus limits protein isoprenylation. In the same way, a reduction of cholesterol biodisponibilitywas controlled (Pattanayak et al. 2009; Ni et al. 2012; Dahham et al.2016).

Safety Profile

Poison by intravenous route. Moderately toxic by ingestion, subcutaneous, and intramuscular routes. A severe human skin irritant. Combustible liquid. When heated to decomposition it emits acrid smoke and irritating fumes.

Synthesis

By fractional distillation from those essential oils rich in geraniol, or synthetically from myrcene.

Metabolism

Geraniol is metabolized in the rabbit by ω-oxidation and by reduction of an α β-unsaturated bond (Parke, 1968). The products of geraniol metabolism are 'Hildebrandt acid' and 7-carboxy-3-methylocta-6-enoic acid. The latter acid is optically active (Williams, 1959).

Purification Methods

Purify geraniol by ascending chromatography or by thin layer chromatography on plates of kieselguhr G with acetone/water/liquid paraffin (130:70:1) as solvent system. Hexane/ethyl acetate (1:4) is also suitable. Also purify it by GLC on a silicone-treated column of Carbowax 20M (10%) on Chromosorb W (60-80 mesh). [Porter Pure Appl Chem 20 499 1969.] Store it in full, tightly sealed containers in the cool and protect from light. It has a pleasant odour. [cf p 681, Beilstein 1 IV 2277.]

InChI:InChI=1/C10H18O/c1-9(2)5-4-6-10(3)7-8-11/h5,7,11H,4,6,8H2,1-3H3/b10-7+

Synthetic route

3,7-dimethyl-2,6-octadienal (141-27-5) → Geraniol (106-24-1)

Conditions	Yield
With phosphotungstic acid; sodium tetrahydroborate In methanol	100%
With sodium tetrahydroborate; sodium hydroxide In water at 35℃; for 0.416667h; pH=12; Reagent/catalyst; Green chemistry;	99%
antimony(III) chloride; aluminium In water; N,N-dimethyl-formamide for 1h; Ambient temperature;	98%

3,7-dimethylocta-2,6-dien-1-yl ethanoate (16409-44-2) → Geraniol (106-24-1)

Conditions	Yield
With potassium carbonate In methanol Inert atmosphere;	100%

3,7-dimethyl-2E,6-octadien-1-yl acetate (105-87-3) → Geraniol (106-24-1)

Conditions	Yield
With potassium carbonate In methanol at 25℃; for 0.166667h;	99%
With methanol at 80℃; for 6h; Inert atmosphere; Schlenk technique;	99%
With methanol; oxo[hexa(trifluoroacetato)]tetrazinc for 12h; Reflux; Inert atmosphere;	96%

(2E)-3,7-dimethyl-1-triphenylmethoxy-2,6-octadiene (92464-82-9) → Geraniol (106-24-1)

Conditions	Yield
With naphthalene; lithium In tetrahydrofuran at -78℃; for 1.5h;	99%

geranyl 2-tetrahydropyranyl ether (59632-99-4) → Geraniol (106-24-1)

Conditions	Yield
With dimethylbromosulphonium bromide In methanol; dichloromethane at 20℃; for 2h;	98%
Nafion-H In methanol for 6h;	97%
With lithium perchlorate at 55℃; Product distribution; acid catalyst generated by electrolysis;	96%

geraniol tert-butyldimethylsilyl ether (80873-81-0) → Geraniol (106-24-1)

Conditions	Yield
With Decaborane In tetrahydrofuran; methanol at 20℃; for 1h;	98%
With iron(III) chloride In methanol at 20℃; for 0.5h;	96%
With iron(III) p-toluenesulfonate hexahydrate In methanol at 20℃; for 2.25h; chemoselective reaction;	86%

{[(2E)-3.7-dimethyl-2,6-octadien-1-yl]oxy}(triethyl)silane (160882-63-3) → Geraniol (106-24-1)

Conditions	Yield
10percent Pd/C In methanol at 20℃; for 2h;	98%

C25H32O3 (1204225-79-5) → Geraniol (106-24-1)

Conditions	Yield
With ethanol; copper(ll) bromide at 20℃; for 0.5h;	98%

O-(trans-3,7-dimethylocta-2,6-dien-1-yl)trimethylsilane (72106-90-2) → Geraniol (106-24-1)

Conditions	Yield
Tetrabutyl-1,3-diisothiocyanato-distannoxane In methanol for 16h; Ambient temperature;	95%
1,3-di(NCS)-tetrabutyldistannoxane In methanol for 16h; Ambient temperature; Deprotection of silyl ethers;	95%
With water; aluminium In hexane for 0.0833333h; Ambient temperature;	90%

(E)-3,7-dimethyl-1-(2-phenylallyloxy)-2,6-octadiene → Geraniol (106-24-1)

Conditions	Yield
With tert.-butyl lithium In tetrahydrofuran; pentane at -78℃; for 0.5h;	95%

ethyl (E)-3,7-dimethylocta-2,6-dienoate (32659-21-5) → Geraniol (106-24-1)

Conditions	Yield
With diisobutylaluminium hydride In hexane at -70 - 10℃;	92%
With diisobutylaluminium hydride In tetrahydrofuran	72%
With lithium aluminium tetrahydride Yield given;
With diisobutylaluminium hydride In tetrahydrofuran at -78 - 22℃; for 3h; Inert atmosphere;
With diisobutylaluminium hydride In diethyl ether; hexane at -78℃; for 3h; Inert atmosphere;

geranyl benzyl ether (52188-73-5) → Geraniol (106-24-1)

Conditions	Yield
With lithium; ethylenediamine In tetrahydrofuran at -10℃; for 3.33333h;	92%

2-{(E)-2-[((E)-3,7-Dimethyl-octa-2,6-dienyloxy)-dimethyl-silanyl]-vinyl}-phenol (152753-75-8) → Geraniol (106-24-1)

Conditions	Yield
In acetonitrile for 0.5h; Irradiation;	91%

(2R,3R)-2-((E)-3,7-Dimethyl-octa-2,6-dienyloxy)-3-heptadecafluorooctyl-tetrahydro-pyran → Geraniol (106-24-1)

Conditions	Yield
With methanol; toluene-4-sulfonic acid In tetrahydrofuran at 70℃; for 24h; deprotection of alcoholic OH;	91%

3-{(E)-2-[((E)-3,7-Dimethyl-octa-2,6-dienyloxy)-diisopropyl-silanyl]-vinyl}-naphthalen-2-ol (342890-05-5) → Geraniol (106-24-1) + 2,2-diisopropyl-2H-1-oxa-2-sila-anthracene

Conditions	Yield
In methanol for 0.75h; Irradiation;	A 90% B 91%

3,7-dimethyl-1-[tris(trimethylsilyl)silyl]-2,6-octadien-1-ol → Geraniol (106-24-1)

Conditions	Yield
With methanol In dichloromethane at 10℃; for 0.5h; Product distribution; Irradiation;	90%
In methanol; dichloromethane desilylation; Photolysis;	90%

2-((E)-3,7-Dimethyl-octa-2,6-dienyloxymethyl)-1,3-dimethyl-benzene → Geraniol (106-24-1)

Conditions	Yield
With lithium; ethylenediamine In tetrahydrofuran at -10℃; for 2h;	88%

Maltose (133-99-3, 490-37-9, 2152-98-9, 4482-75-1, 5965-66-2, 13299-27-9, 13360-52-6, 14641-93-1, 15548-43-3, 16462-44-5, 16984-36-4, 16984-38-6, 20869-27-6, 22688-72-8, 27452-49-9, 29276-55-9, 30608-12-9, 34481-13-5, 37169-60-1, 37169-64-5, 64234-01-1, 64234-02-2, 75281-88-8, 80446-85-1, 84413-57-0, 92344-56-4, 93221-87-5, 93301-77-0, 94799-29-8, 100427-98-3, 100428-00-0, 101312-82-7, 102046-24-2, 102046-25-3, 109432-00-0, 109432-02-2, 109432-04-4, 109432-08-8, 135268-49-4, 138231-26-2, 140461-59-2, 145414-22-8, 145414-26-2, 146339-75-5, 146339-76-6, 149116-55-2, 6363-53-7) + Nerol (106-25-2) → Geraniol (106-24-1) + geranyl α-D-glucopyranoside (151921-84-5) + neryl-α-D-glucopyranoside

Conditions	Yield
With Agrobacterium sp. M-12 cell extract In aq. phosphate buffer at 40℃; for 72h; pH=7; Reagent/catalyst; Temperature; Enzymatic reaction;	A n/a B n/a C 87.6%

1-(1-geranyloxy)-1-(2-nitrophenyl)-2,4-hexadiene → Geraniol (106-24-1) + 2-Methyl-2,4a-dihydro-[1,2]oxazino[2,3-a]indol-5-one

Conditions	Yield
In methanol for 1.75h; Decomposition; Irradiation;	A 84% B 60%

(E)-1-(1-((3,7-dimethylocta-2,6-dien-1-yl)oxy)methyl)-4-methoxybenzene (82529-81-5) → Geraniol (106-24-1)

Conditions	Yield
With 2,3-dicyano-5,6-dichloro-p-benzoquinone In dichloromethane; water for 1h; Ambient temperature;	81.9%
With lithium; ethylenediamine In tetrahydrofuran at -10℃; for 4h;	55%
With dimethylsulfide; magnesium bromide In dichloromethane for 8h; Ambient temperature;	35%
With N1,N1,N12,N12-tetramethyl-7,8-dihydro-6H-dipyrido[1,2-a:2,1'-c][1,4]diazepine-2,12-diamine In N,N-dimethyl-formamide for 72h; Inert atmosphere; Glovebox; UV-irradiation;	10%

(E)-Geranyl chloroacetate (60758-60-3) → Geraniol (106-24-1)

Conditions	Yield
With sodium tetrahydroborate In ethanol at 0 - 20℃; Inert atmosphere;	80%

2-{(E)-2-[((E)-3,7-Dimethyl-octa-2,6-dienyloxy)-diisopropyl-silanyl]-vinyl}-phenol (152753-81-6) → Geraniol (106-24-1)

Conditions	Yield
In acetonitrile for 0.5h; Irradiation;	75%

{[(2E)-3.7-dimethyl-2,6-octadien-1-yl]oxy}(triethyl)silane (160882-63-3) → 3,7-dimethyl-2,6-octadienal (141-27-5) + Geraniol (106-24-1)

Conditions	Yield
With water; 1-hydroxy-3H-benz[d][1,2]iodoxole-1,3-dione In dimethyl sulfoxide at 20℃; for 0.75h;	A 73.6% B 24.4%

1-((E)-3,7-Dimethyl-octa-2,6-dienyloxymethoxy)-4-methoxy-benzene (124068-38-8) → Geraniol (106-24-1)

Conditions	Yield
With ammonium cerium(IV) nitrate In water; acetonitrile at 0℃; for 0.5h; Product distribution; different reagents, times, solvents, temperatures and catalyst;	73%

(E)-1-(((3,7-dimethylocta-2,6-dien-1-yl)oxy)methyl)-2-methoxybenzene (1426824-93-2) → Geraniol (106-24-1) + 2-methylmethoxybenzene (578-58-5)

Conditions	Yield
With N1,N1,N12,N12-tetramethyl-7,8-dihydro-6H-dipyrido[1,2-a:2,1'-c][1,4]diazepine-2,12-diamine In N,N-dimethyl-formamide for 72h; Inert atmosphere; Glovebox; UV-irradiation;	A 73% B 23%

1-hydroxy-3-phenylsulfinylmethyl-7-methylocta-2Z,6-diene (112766-85-5) → Geraniol (106-24-1)

Conditions	Yield
With ammonia; sodium In diethyl ether at -70℃; for 0.0833333h;	72%

Nerol (106-25-2) → 3,7-dimethylocta-1,6-dien-3-ol (78-70-6) + Geraniol (106-24-1) + terpineol (98-55-5)

Conditions	Yield
With bis-trimethylsilanyl peroxide; bis(acetylacetonate)oxovanadium In dichloromethane at 25℃; for 7h;	A 70% B 11% C 3%
bis(acetylacetonate)oxovanadium; bis-trimethylsilanyl peroxide In dichloromethane at 25℃; for 7h;	A 70 % Chromat. B 11 % Chromat. C 3 % Chromat.
bis(acetylacetonate)oxovanadium; bis-trimethylsilanyl peroxide In dichloromethane at 25℃; for 7h; Product distribution;	A 70 % Chromat. B 11 % Chromat. C 3 % Chromat.

geranyl benzyl ether (52188-73-5) → Geraniol (106-24-1) + benzoic acid (65-85-0)

Conditions	Yield
With bis(acetylacetonate)oxovanadium; methyl 3,5-bis((1H-1,2,4-triazol-1-yl)methyl)benzoate; oxygen; sodium acetate at 120℃; for 48h;	A 63% B 69%

1-phenylsulfonyl-2-methyl-4-hydroxy-but-2-ene (59830-37-4) + 3-methyl-2-butenylmagnesium chloride (35189-96-9) → Geraniol (106-24-1)

Conditions	Yield
copper acetylacetonate In tetrahydrofuran for 18h; Ambient temperature;	65%

2,3,6,7-tetrabromo-3,7-dimethyl-octan-1-ol (87378-16-3) → Geraniol (106-24-1)

Conditions	Yield
With sodium sulfide; Aliquat 336 In water; benzene for 1h; Ambient temperature;	64%

Geraniol (106-24-1) → Citronellol (106-22-9)

Conditions	Yield
With hydrogen; aluminum oxide; copper In isopropyl alcohol at 90℃; for 12h;	100%
With hydrogen; polymer-supported rhodium catalyst In dichloromethane under 1551.49 Torr; for 10h; Hydrogenation;	96%
With 1,1'-bis(diphenylphosphino)ferrocene; [ruthenium(II)(η6-1-methyl-4-isopropyl-benzene)(chloride)(μ-chloride)]2; Butane-1,4-diol; potassium tert-butylate at 110℃; for 24h; Inert atmosphere;	71%

Geraniol (106-24-1) + acetic anhydride (108-24-7) → 3,7-dimethyl-2E,6-octadien-1-yl acetate (105-87-3)

Conditions	Yield
With pyridine Ambient temperature;	100%
With pyridine In tetrahydrofuran at 0 - 20℃; Acetylation;	100%
With pyridine; dmap at 20℃; for 1h; Acetylation;	99%

Geraniol (106-24-1) → trans-geranyl bromide (6138-90-5)

Conditions	Yield
With phosphorus tribromide In diethyl ether at 0℃; for 2h;	100%
With phosphorus tribromide In diethyl ether at 0℃; for 0.166667h;	100%
With titanium(IV) bromide; N-methylaniline In dichloromethane at -23℃; for 1h;	100%

Geraniol (106-24-1) → 1-chloro-3,7-dimethylocta-2,6-diene (5389-87-7)

Conditions	Yield
With titanium tetrachloride; N-methylaniline In dichloromethane at -23℃; for 1h;	100%
With chloro-trimethyl-silane; potassium carbonate In Petroleum ether at 0℃; for 2h;	97%
With dmap; triethylamine; p-toluenesulfonyl chloride In dichloromethane for 3h; Ambient temperature;	97%

3,4-dihydro-2H-pyran (110-87-2) + Geraniol (106-24-1) → geranyl 2-tetrahydropyranyl ether (59632-99-4)

Conditions	Yield
bis(trimethylsilyl)sulphate In dichloromethane; 1,2-dichloro-ethane at 0℃; for 0.25h;	100%
With toluene-4-sulfonic acid In dichloromethane for 3h; Ambient temperature;	99.5%
With pyridinium p-toluenesulfonate In dichloromethane at 20℃;	99%

Geraniol (106-24-1) → [3-methyl-3-(4-methylpent-3-enyl)oxiran-2-yl]methanol (50727-94-1)

Conditions	Yield
With tetrahexylammonium tetrakis(diperoxomolybdo)phosphate In chloroform at 40℃; for 7h;	100%
With tert.-butylhydroperoxide; bis(acetylacetonate)oxovanadium In chlorobenzene at 80℃; for 5h;	100%
With tetrabutylphosphonium peroxotantalate; dihydrogen peroxide In water at 0℃; for 3.5h; Schlenk technique; regioselective reaction;	100%

Geraniol (106-24-1) → (2S,3S)-2,3-epoxygeraniol (82188-73-6)

Conditions	Yield
With titanium(IV) isopropylate; tert.-butylhydroperoxide; L-(+)-diisopropyl tartrate; 4 A molecular sieve In dichloromethane at -23℃; for 2h;	100%
With titanium(IV) isopropylate; tert.-butylhydroperoxide; diethyl (2S,3S)-tartrate In dichloromethane at -40℃; for 5h; Sharpless Asymmetric Epoxidation; Inert atmosphere; enantioselective reaction;	99%
With titanium(IV) isopropylate; tert.-butylhydroperoxide; diethyl (2R,3R)-tartrate In dichloromethane at -25 - -20℃; Molecular sieve;	98%

Geraniol (106-24-1) → 3,7-dimethyl-2,6-octadienal (141-27-5)

Conditions	Yield
With manganese(IV) oxide In hexane at 0℃; for 6h;	100%
With manganese(IV) oxide	100%
With manganese(IV) oxide In hexane at 0℃; for 6h; Product distribution; also with activated MnO2, other substrates;	100%

Geraniol (106-24-1) + diethyl chlorophosphate (814-49-3) → (E)-3,7-dimethylocta-2,6-dien-1-yl diethyl phosphate (60699-32-3)

Conditions	Yield
With pyridine In diethyl ether at -15 - 20℃;	100%
In pyridine at 0 - 20℃; for 1h;	98%
With pyridine In diethyl ether at -15 - 20℃; for 3h;	94%

Geraniol (106-24-1) + tert-butyldimethylsilyl chloride (18162-48-6) → geraniol tert-butyldimethylsilyl ether (80873-81-0)

Conditions	Yield
With N-ethyl-N,N-diisopropylamine In dichloromethane at 20℃;	100%
With 1H-imidazole In N,N-dimethyl-formamide	99%
With 1H-imidazole In N,N-dimethyl-formamide	98%

Geraniol (106-24-1) + tert-butylchlorodiphenylsilane (58479-61-1) → (E)-tert-butyl[(3,7-dimethylocta-2,6-dien-1-yl)oxy]diphenylsilane (139109-03-8, 117638-12-7)

Conditions	Yield
With 1H-imidazole In N,N-dimethyl-formamide for 0.25h; Ambient temperature;	100%
With 1H-imidazole In N,N-dimethyl-formamide at 20℃; for 1h; Silylation;	100%
With 1H-imidazole In N,N-dimethyl-formamide at 20℃; for 1h;	100%

Geraniol (106-24-1) → (E)-5-(3,3-dimethyloxiran-2-yl)-3-methylpent-2-en-1-ol (40036-54-2)

Conditions	Yield
With tert.-butylhydroperoxide In acetonitrile at 80℃; for 24h; Catalytic behavior; Reagent/catalyst;	100%
With urea hydrogen peroxide adduct; methyltrioxorhenium(VII) In dichloromethane at 20℃; for 0.25h;	73%
Stage #1: Geraniol With N-Bromosuccinimide; dimethyl sulfoxide at 10℃; for 0.5h; Inert atmosphere; Stage #2: With 1,8-diazabicyclo[5.4.0]undec-7-ene In dimethyl sulfoxide at 0℃; for 0.5h; Inert atmosphere;	60%

vinyl acetate (108-05-4) + Geraniol (106-24-1) → 3,7-dimethyl-2E,6-octadien-1-yl acetate (105-87-3)

Conditions	Yield
With dilithium tetra(tert-butyl)zincate In toluene at 0℃; for 1h; Inert atmosphere;	100%
With N,N'-bismesityl-imidazol-2-ylidene In tetrahydrofuran at 20℃; for 1h;	99%
1,3-bis(2,4,6-trimethyl-phenyl)imidazol-2-ylidene In tetrahydrofuran at 20℃; for 1h;	99%

Geraniol (106-24-1) + ethyl dihydrocinnamate (2021-28-5) → (E)-3,7-dimethylocta-2,6-dien-1-yl 3-phenylpropanoate

Conditions	Yield
[Cl(C6F13C2H4)2SnOSn(C2H4C6F13)2Cl]2 In toluene at 150℃; for 16h;	100%

Geraniol (106-24-1) + phenyl isocyanate (103-71-9) → (E)-3,7-dimethylocta-2,6-dien-1-yl phenylcarbamate (57706-89-5)

Conditions	Yield
With MoCl2O2(dmf)2 In dichloromethane at 20℃; for 0.333333h;	100%
In pyridine at 5 - 20℃; for 12h;	88%
Stage #1: Geraniol; phenyl isocyanate In toluene for 1h; Heating; Stage #2: With 5-hydroxymethyl-2-norbornene In toluene Heating; Stage #3: With [{1,3-bis(mesyl)imidazolidin-2-yl}RuCl2(PCy3)(=CHPh)] In dichloromethane for 0.5h; Heating; Further stages.;	78%

Geraniol (106-24-1) + 3-Phenylpropionic acid (501-52-0) → (E)-3,7-dimethylocta-2,6-dien-1-yl 3-phenylpropanoate

Conditions	Yield
With [Cl(C6F13C2H4)2SnOSn(C2H4C6F13)2Cl]2 In various solvent(s) at 150℃; for 10h;	100%
Stage #1: 3-Phenylpropionic acid With iodine; triphenylphosphine In dichloromethane at 20℃; for 0.166667h; Stage #2: With gadolinium(III) trifluoromethanesulfonate In dichloromethane at 50℃; for 0.5h; Stage #3: Geraniol In dichloromethane	71%
With dmap; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride In dichloromethane at 20℃; for 16h;
With dmap; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride In dichloromethane at 20℃;

Geraniol (106-24-1) → (E)-geranyl-H-phosphinic acid (701279-14-3)

Conditions	Yield
With tris(dibenzylideneacetone)dipalladium (0); 9,9-dimethyl-4,6-bis(diphenylphosphino)xanthene; hypophosphorous acid In N,N-dimethyl-formamide at 85℃;	100%
With hypophosphorous acid; tris-(dibenzylideneacetone)dipalladium(0); 4,5-bis(diphenylphos4,5-bis(diphenylphosphino)-9,9-dimethylxanthenephino)-9,9-dimethylxanthene In N,N-dimethyl-formamide at 85℃;

Geraniol (106-24-1) → C11H20O2

Conditions	Yield
With tert.-butylhydroperoxide In chloroform for 4h; Catalytic behavior; Reflux;	100%

Geraniol (106-24-1) + acetic acid (64-19-7) → 3,7-dimethyl-2E,6-octadien-1-yl acetate (105-87-3)

Conditions	Yield
With Candida antarctica lipase B at 50℃; for 4h; Molecular sieve; Ionic liquid; Green chemistry; Enzymatic reaction;	99.9%
With hydroquinone at 120℃; Temperature; Reagent/catalyst;	99.2%
With 1,3-propanesultone; N-ethyl-N-methylbutan-1-amine; toluene-4-sulfonic acid at 110℃; for 2h; Temperature; Reagent/catalyst;	97%

Geraniol (106-24-1) + butyric acid (107-92-6) → Geranyl butyrate (106-29-6)

Conditions	Yield
With Candida antarctica lipase B at 50℃; for 4h; Molecular sieve; Ionic liquid; Green chemistry; Enzymatic reaction;	99.9%
With sodium hydroxide at 80℃; for 8h;	66.94%
In hexane at 30℃; for 72h; Corynebacterium sp. S-401;	23%

Geraniol (106-24-1) + propionic acid (802294-64-0) → geranyl propionate (105-90-8)

Conditions	Yield
With Candida antarctica lipase B at 50℃; for 4h; Molecular sieve; Ionic liquid; Green chemistry; Enzymatic reaction;	99.6%
With dmap; dicyclohexyl-carbodiimide In dichloromethane at 0 - 23℃; for 0.5h;	90%
In hexane at 30℃; for 72h; Corynebacterium sp. S-401;	13%
In water at 30℃; for 18h; lipase from Aspergillus niger; Yield given;
With candida antarctica B (CALB) lipase immobilized in polyurethane (PU) foam Enzymatic reaction;

(phenylthio)acetic acid chloride (7031-27-8) + Geraniol (106-24-1) → 3,7-dimethyl-2(E),6-octadienyl (phenylthio)acetate (87519-21-9)

Conditions	Yield
With pyridine In dichloromethane for 3h;	99.3%

Geraniol (106-24-1) + pivaloyl chloride (3282-30-2) → (E)-3,7-dimethylocta-2,6-dien-1-yl pivalate (85796-37-8)

Conditions	Yield
With pyridine; 1H-imidazole at 20℃; for 1h;	99%
With pyridine In dichloromethane at 20℃; for 2h; Inert atmosphere;	96%
With pyridine In dichloromethane at 20℃; for 2h; Inert atmosphere;	96%

Geraniol (106-24-1) + 3-methylbut-3-enoyl chloride (3350-77-4) → (E)-geranyl 3-methyl-3-butenoate (84825-22-9)

Conditions	Yield
With triethylamine In dichloromethane at -78℃; for 3h;	99%
With pyridine In diethyl ether for 1.5h;	86%

Geraniol (106-24-1) → (+/-)-2,3-epoxygeraniol (62960-04-7)

Conditions	Yield
With tert.-butylhydroperoxide; V(IV)O(salen derivative) In carbon dioxide; water at 45℃; under 165487 Torr; for 48h;	99%
With dihydrogen peroxide; W2O11(2-)*2Ph3PCH2Ph(1+) In 1,2-dichloro-ethane at 0℃; for 24h;	98%
With tert.-butylhydroperoxide; chromium silicalite-2 In methanol at 65℃; for 5h;	95%

Geraniol (106-24-1) + benzoyl chloride (98-88-4) → (E)-geranyl benzoate (94-48-4)

Conditions	Yield
With pyridine; dmap In diethyl ether for 20h; Inert atmosphere; Schlenk technique;	99%
Stage #1: Geraniol; benzoyl chloride In dichloromethane at 20℃; Stage #2: With poly{trans-bicyclo[2.2.1]hept-5-ene-2,3-di(chlorocarbonyl)} In dichloromethane Heating;	94%
With pyridine; dmap In diethyl ether for 2h; Ambient temperature; Yield given;

Geraniol (106-24-1) + propynoic acid methyl ester (922-67-8) → methyl (E)-3-{[(E)-3,7-dimethylocta-2,6-dien-1-yl]oxy}acrylate

Conditions	Yield
With 1,4-diaza-bicyclo[2.2.2]octane In dichloromethane	99%
With tributylphosphine In dichloromethane for 0.05h; Ambient temperature;	91%

3,3-Dimethylacryloyl chloride (3350-78-5) + Geraniol (106-24-1) → (E)-geranyl 3-methyl-3-butenoate (84825-22-9)

Conditions	Yield
With triethylamine In dichloromethane at -78℃; for 3h;	99%

Upstream product

• 79-43-6 dichloro-acetic acid 
• 115-18-4 2-methyl-3-buten-2-ol 
• 126-91-0 linalool 
• 78-70-6 3,7-dimethylocta-1,6-dien-3-ol 
• 1189-09-9 methyl geranate 
• 108-24-7 acetic anhydride 
• 64-19-7 acetic acid 
• 78-79-5 isoprene 
• 2414-98-4 magnesium ethylate 
• 67-63-0 isopropyl alcohol 
• 5392-40-5 (E/Z)-3,7-dimethyl-2,6-octadienal 
• 555-31-7 aluminum isopropoxide 
• 70473-50-6 2-(phenylthio)-3-methyl-3-buten-1-ol 
• 870-63-3 prenyl bromide 

Downstream Products

• 5392-40-5 (E/Z)-3,7-dimethyl-2,6-octadienal 
• 14576-08-0 4-(2-methoxypropan-2-yl)-1-methylcyclohex-1-ene 
• 56172-46-4 trans-crotonic acid-(3,7-dimethyl-octa-2,6-dienyl ester) 
• 106-29-6 Geranyl butyrate 
• 110-93-0 6-Methyl-hept-5-en-2-on 
• 106-25-2 Nerol 
• 1188-06-3 geranyl 2-methylpropanoate 
• 68892-05-7 undec-10-enoic acid-(3,7-dimethyl-octa-2t,6-dienyl ester) 
• 7704-04-3 2-geranyl-5,6-dimethoxy-3-methyl-[1,4]benzoquinone 
• 95439-21-7 (4-phenylazo-phenyl)-carbamic acid geranyl ester 
• 78-70-6 3,7-dimethylocta-1,6-dien-3-ol 
• 106-22-9 Citronellol 
• 4490-10-2 geranyl chloride 
• 471-10-3 linalyl chloride 

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Selective Hydrogenation of Aldehydes Using a Well-Defined Fe(II) PNP Pincer Complex in Biphasic Medium

A biphasic process for the hydrogenation of aldehydes was developed using a well-defined iron (II) PNP pincer complex as model system to investigate the performance of various ionic liquids. A number of suitable hydrophobic ionic liquids based on the N(Tf)2? anion were identified, allowing to immobilize the iron (II) catalyst in the ionic liquid layer and to facilitate the separation of the desired alcohols. Further studies showed that targeted Br?nsted basic ionic liquids can eliminate the need of an external base to activate the catalyst.

Large Pore Bifunctional Titanium-Aluminosilicates: the Inorganic Non-enzymatic Version of the Epoxidase Conversion of Linalool to Cyclic Ethers

Bifunctional aluminosilicate catalysts containing framework Ti are prepared, with two different topologies and pore sizes; these samples contain both acid and oxidizing catalytic sites and are highly selective for carrying out multistep reactions with selectivities close to those obtained with epoxidases, this is shown to occur for the oxidation of linalool to cyclic hydroxy ethers.

Gold catalysis for selective hydrogenation of aldehydes and valorization of bio-based chemical building blocks

Gold catalysts are best known for their selectivity in oxidation reactions, however, there is a promising future for gold in selective hydrogenations. Herein, the hydrogenation of several aldehydes and important bio-based chemical building blocks, namely 5-hydroxymethylfurfural (5-HMF), furfural and vanillin, was performed throughout the combination of Au nanoparticles with Lewis bases. The Au-amine ligand (e.g., 2,4,6-trimethylpyridine) catalytic system could reduce the aldehyde carbonyl group selectively, without reducing alkene moieties or opening the furanic ring that occur on most traditional catalysts. Otherwise, the reduction of nitro group is preferential and the catalytic system was used for the synthesis of furfurylamines, important intermediates in the synthesis of different pharmaceuticals (e.g., furosemide), through the selective reductive amination of furfural starting from nitro-compounds. Moreover, a fully heterogeneous gold catalyst embedded in N-doped carbon (Au@N-doped carbon / TiO2) was able to perform these reactions in successive recycles without the addition of ligands, with impact in the development of a continuous flow process for biomass valorization.

REACTION OF HIGHLY ACTIVE MAGNESIUM WITH ISOPRENE, MYRCENE, OCIMENE, AND PIPERYLENE

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Asymmetric bioreduction of activated alkenes using cloned 12-oxophytodienoate reductase isoenzymes OPR-1 and OPR-3 from Lycopersicon esculentum (tomato): A striking change of stereoselectivity

(Chemical Equation Presented) Tomato source: 12-Oxophytodienoate reductase isoenzymes OPR1 and OPR3 from tomato possess a broad substrate spectrum for the asymmetric bioreduction of α,β-unsaturated enals, enones, dicarboxylic acids, and N-substituted male-imides (see scheme). Stereocomplementary behavior of both isoenzymes was observed in the reduction of a nitroalkene that led to the formation of opposite stereoisomers in high enantiomeric excess.

SELECTIVE REDUCTION OF ALDEHYDES IN PRESENCE OF A KETONE WITH CHLOROTRIMETHYLSILANE AND NICKEL BORIDE

It has been shown that a combination of chlorotrimethylsilane and nickel boride effects the chemoselective reduction of an aldehyde in presence of a ketonic carbonyl group.

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Lipase-catalyzed separation of geometrical isomers: Geraniol-nerol

The substrate/lipase ratio as well as pH of the buffer medium played important roles in the resolution of geometrical isomeric mixture of geraniol-nerol. Based on the results, an immobilized lipase from Pseudomonas fluorescens (PFL) was found effective in selective transesterifications whereas Pseudomonas sp. Lipase (PSL) was found to be useful in hydrolyzing the esters. Copyright

Functional investigation and applications of the acetylesterase activity of the Citrus sinensis (L.) Osbeck peel

The hydrolysis of acetyl moieties on a set of commercially relevant substrates was performed by employing the whole tissue of Citrus sinensis (L.) Osbeck peel as an efficient biocatalyst in mild reaction conditions with high degree of regioselectivity. The reaction is done in aqueous media and the product is easily recovered. Optimal reaction conditions were deduced and two practical applications were investigated: the elaboration of acetylglicerols and the preparation of vitamin K1 precursor. Peel waste (flavedo and albedo) from orange juice manufacturing was successfully employed as a biocatalyst.

A mild and selective deprotection of p-methoxybenzyl (PMB) ether by magnesium bromide diethyl etherate-methyl sulfide

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Hydrolysis of isoprenyl diphosphates with the acid phosphatase from Cinnamomum camphora

Direct observations of the enzymatic hydrolysis of C10 acyclic allylic isoprenyl diphosphates by an acid phosphatase from the leaves of Cinnamomum camphora (camphor tree) were made using 1H and 31P NMR spectrometers. The measurements indicated that the allylic primary diphosphates, geranyl diphosphate and neryl diphosphate, were hydrolysed to their corresponding alcohols in a sequential manner via their corresponding monophosphates, whereas the allylic tertiary diphosphate, linalyl diphosphate, was hydrolysed only to its corresponding monophosphate.

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Syntheses of α,β-Epoxy Silyl Ketones

The synthesis of the α,β-epoxy-acylsilanes 1 and 2 starting from the allylic silyl alcohols (E)- and (Z)-3, respectively, by epoxidation with t-BuOOH/VO(acac)2 followed by oxidation with Collins reagent (CrO3/pyridine) in up to 70percent overall yields, is described.The acid-catalyzed rearrangement of the epoxy-silyl alcohols 4A+B and 5A+B led to the novel unstable diastereomeric α-silyl-β-hydroxy-aldehydes 9 and 10, respectively.The structure of 10 was established by X-ray crystal-structure analysis of the corresponding alcohol 11.

ISOMERIZATION OF ALLYLIC ALCOHOLS CATALYZED BY VANADIUM OR MOLYBDENUM COMPLEXES.

Isomerization of primary allylic alcohols proceeds in dichloromethane at 25 degree C in the presence of the catalyst prepared in situ from VO(acac)//2 or MoO//2(acac)//2, and Me//3SiOOSiMe//3 to give tertiary isomers in good yields. The catalysts are also effective for the rearrangements of sec. yields tert. allylic alcohols. The isomerization of an allenyl allylic alcohol, 6-methyl-1,2,5-heptatrien-4-ol, gives either (E)-2-methyl-3,5,6-heptarien-2-ol or (E)-6-methyl-3,5-heptadien-2-one selectively depending on the reaction conditions.

A mild, efficient, and inexpensive protocol for the selective deprotection of TBDMS ethers using KHSO4

Potassium hydrogensulfate in 30% aq. methanol deprotects a variety of tert-butyldimethylsilyl ethers at room temperature in excellent yields.

Titanyl acetylacetonate as an efficient catalyst for regioselective 1,2-reduction of α,β-unsaturated carbonyl compounds and conversion of α-diketones & acyloins to vicinal diols with sodium borohydride

α,β-Unsaturated aldehydes and ketones were reduced readily and exclusively to their corresponding allylic alcohols with NaBH4 and catalytic amounts of titanyl acetylacetonate at room temperature. Reduction reactions were carried out in CH3CN or THF. This reducing system was also efficient for the reduction of α-diketones and acyloins to their corresponding vicinal diols in CH3CN.

Three-Dimensionally Hierarchical Pt/C Nanocomposite with Ultra-High Dispersion of Pt Nanoparticles as a Highly Efficient Catalyst for Chemoselective Cinnamaldehyde Hydrogenation

A monolithic carbon-supported Pt nanocomposite with an interconnected three-dimensionally hierarchical porous carbon framework and ultra-high dispersion of Pt nanoparticles (Pt/3DHPC) is synthesized by using an effective “liquid phase impregnation template” strategy. The obtained Pt/3DHPC possesses rich mesoporosity and a low amount of oxygen-containing functional groups, which notably improve the accessible internal surface area of macropores, number of active Pt sites, and electron transfer ability. When used as a catalyst for the selective cinnamaldehyde (CMA) hydrogenation towards cinnamyl alcohol (CMO), Pt/3DHPC exhibits high CMA conversion (92.7 %) and CMO selectivity (91.1 %) at 1 h reaction time, and the corresponding activity (1553.7 h?1) greatly surpasses not only the single-sized mesoporous carbon and microporous activated carbon-supported counterparts but also the previously reported Pt catalysts dispersed on other forms of carbon. Furthermore, Pt/3DHPC can be reused at least fifteen times without pronounced decay owing to the strong interaction between Pt and carbon. The present work demonstrates the validity of multiscale control in carbon-supported Pt catalysts by overall consideration of the mass transportation, and the accessibility, quantity, and capability of active sites towards chemoselective hydrogenation of CMA, which is expected to be extended to other catalysis-related processes.

Regioselective Hydroxylations of 1,3-Dienes via Hydrocobaltation Reactions. Facile Conversion of Myrcene to Geraniol and to (+/-)-Linalool

Regioselective (1,4-) hydrocobaltation of myrcene (1) leads to a 2:1 mixture of (E)- and (Z)-allylcobaloximes (2) which can be converted via the corresponding hydroxylamines (5) to geraniol (6a) and nerol (6b); by contrast, in the presence of molecular oxygen, (2) is converted into the peroxyallylcobalt complex (7), a precursor to linalool (8) and to linalool oxide (10).

A domain swapping approach to elucidate differential regiospecific hydroxylation by geraniol and linalool synthases from perilla

Geraniol and linalool are acyclic monoterpenes found in plant essential oils that have attracted much attention for their commercial use and in pharmaceutical studies. They are synthesized from geranyl diphosphate (GDP) by geraniol and linalool synthases, respectively. Both synthases are very similar at the amino acid level and share the same substrate; however, the position of the GDP to which they introduce hydroxyl groups is different. In this study, the mechanisms underlying the regiospecific hydroxylation of geraniol and linalool synthases were investigated using a domain swapping approach and sitedirected mutagenesis in perilla. Sequences of the synthases were divided into ten domains (domains I to IV-4), and each corresponding domain was exchanged between both enzymes. It was shown that different regions were important for the formation of geraniol and linalool, namely, domains IV-1 and -4 for geraniol, and domains III-b, III-d, and IV-4 for linalool. These results suggested that the conformation of carbocation intermediates and their electron localization were seemingly to be different between geraniol and linalool synthases. Further, five amino acids in domain IV-4 were apparently indispensable for the formation of geraniol and linalool. According to three-dimensional structural models of the synthases, these five residues seemed to be responsible for the different spatial arrangement of the amino acid at H524 in the case of geraniol synthase, while N526 is the corresponding residue in linalool synthase. These results suggested that the side-chains of these five amino acids, in combination with several relevant domains, localized the positive charge in the carbocation intermediate to determine the position of the introduced hydroxyl group.

Metal-doped mesoporous ZrO2catalyzed chemoselective synthesis of allylic alcohols from Meerwein-Ponndorf-Verley reduction of α,β-unsaturated aldehydes

Meerwein-Ponndorf-Verley reduction (MPVr) is a sustainable route for the chemoselective transformation of α,β-unsaturated aldehydes. However, tailoring ZrO2 catalysts for improved surface-active sites and maximum performance in the MPV reaction is still a challenge. Here, we synthesized mesoporous zirconia (ZrO2) and metal-doped zirconia (M_ZrO2, M = Cr, Mn, Fe, and Ni). The incorporation of metal dopants into zirconia's crystal framework alters its physico-chemical properties such as surface area and total acidity-basicity. The prepared catalysts were evaluated in the MPVr using 2-propanol as a hydrogen donor under mild reaction conditions. The catalysts' remarkable reactivity depends mainly on their surface mesostructure's intrinsic properties rather than the specific surface area. Cr_ZrO2, which is stable and sustainable, presented superior activity and 100% selectivity to unsaturated alcohols. The synergistic effect between Cr and Zr species in the binary oxide facilitated the Lewis acidity-induced performance of the Cr_ZrO2 catalyst. Our work presents the first innovative application of a well-designed mesoporous Cr_ZrO2 in the green synthesis of unsaturated alcohols with exceptional reactivity. This journal is

Use of short time-on-stream attenuated total internal reflection infrared spectroscopy to probe changes in adsorption geometry for determination of selectivity in the hydrogenation of citral

A new experimental procedure based on attenuated total reflection infrared spectroscopy has been developed to investigate surface species under liquid phase reaction conditions. The technique has been tested by investigating the enhanced selectivity in the hydrogenation of α,β-unsaturated aldehyde citral over a 5% Pt/SiO2 catalyst toward unsaturated alcohols geraniol/nerol, which occurs when citronellal is added to the reaction. The change in selectivity is proposed to be the result of a change in the citral adsorption mode in the presence of citronellal. Short time on stream attenuated total internal reflection infrared spectroscopy has allowed identification of the adsorption modes of citral. With ssno citronellal, citral adsorbs through both the C = C and C = O groups; however, in the presence of citronellal, citral adsorption occurs through the C = O group only, which is proposed to be the cause of the altered reaction selectivity.

Me3SI-promoted chemoselective deacetylation: a general and mild protocol

A Me3SI-mediated simple and efficient protocol for the chemoselective deprotection of acetyl groups has been developedviaemploying KMnO4as an additive. This chemoselective deacetylation is amenable to a wide range of substrates, tolerating diverse and sensitive functional groups in carbohydrates, amino acids, natural products, heterocycles, and general scaffolds. The protocol is attractive because it uses an environmentally benign reagent system to perform quantitative and clean transformations under ambient conditions.