27644-06-0

Upstream product

• 106-24-1 Geraniol 
• 100-52-7 benzaldehyde 
• 60699-29-8 (Z)-3,7-dimethylocta-2,6-dien-1-yl diethyl phosphate 
• 60699-32-3 (E)-3,7-dimethylocta-2,6-dien-1-yl diethyl phosphate 
• 25996-10-5 (Z)-neryl bromide 
• 6138-90-5 trans-geranyl bromide 
• 20536-36-1 neryl chloride 
• 67883-63-0 (E)-3,7-dimethyl-1-tributylstannylocta-2,6-diene 
• 35266-82-1 (E)-((3,7-dimethylocta-2,6-dien-1-yl)oxy)benzene 
• 78-70-6 3,7-dimethylocta-1,6-dien-3-ol 
• 5389-87-7 1-chloro-3,7-dimethylocta-2,6-diene 
• 92097-30-8 (Z)-3,7-dimethyl-1-tributylstannylocta-2,6-diene 
• 372023-59-1 ((Z)-3,7-dimethyl-2,6-octadienyl)(trichloro)silane 
• 4490-10-2 geranyl chloride 

Relevant academic research and scientific papers

Forging C-C Bonds with Hindered Nucleophiles and Carbonyl Electrophiles: Reactivity and Selectivity of Allylic Tin Reagents/n-BuLi

Under activation with n-BuLi, trialkylstannanes containing crotyl-, geranyl-, and phenyldienylmethyl appendages were reacted with efficiency and selectivity to various ketone and enone electrophiles with low reactivity. The straightforward process gives access to tertiary alcohols that are vicinal to quaternary carbons. With α,α′-dimethoxy-γ-pyrone, on the other hand, the grafting of a dienyl side chain was effected to prepare dienyl α′-methoxy-γ-pyrone in a stereo- and regioselective and convergent manner. Furthermore, the advantages of this route were highlighted for the preparation of organolithium species at low temperature with the formation of a minimum amount of salts. Synthetic manipulations were demonstrated to illustrate the potential of the chemistry for constructing acyclic and cyclic terpene scaffolds.

Enantioselective Synthesis of Quaternary Stereocenters via Chromium Catalysis

Asymmetric allylation of aldehydes with γ-disubstituted allyl halides has been achieved in the presence of a sulfonamide/oxazoline chromium complex. A variety of synthetically useful α-homoallylic alcohols with two consecutive stereogenic centers, including one quaternary carbon, can be accessed in a highly diastereoselective and enantioselective manner.

Dibutyltin oxide catalyzed allyl-transfer reaction from tertiary homoallylic alcohols to aldehydes

A catalytic allyl-transfer reaction from tertiary homoallylic alcohols to aldehydes was achieved using dibutyltin oxide as a catalyst in toluene under reflux conditions. Various secondary homoallylic alcohols were prepared in high yield (up to 99%). When β-alkylated tertiary homoallylic alcohols were used, branched products were exclusively obtained. Georg Thieme Verlag Stuttgart.

Direct preparation of allylic indium(III) reagents from allylic alcohols via a reductive transmetalation of π-allylnickel(II) with indium(I) iodide

InI-mediated direct allylation of carbonyl compounds with allylic alcohols proceeded smoothly with catalytic amounts of Ni(acac)2 and PPh 3 to give the corresponding homoallylic alcohols in high yields. Allylindium compounds were shown to be the real allylating agents in the present system. Substituted allylic alcohols gave branched homoallylic alcohols with syn-selectivity irrespective of the geometry of the starting allylic alcohols, whereas high anti-selectivity was observed when a bulky substituent is present in the allylic alcohols. The outcome of the diastereoselectivity is discussed on the basis of the reaction mechanism, comparing with the corresponding Pd-catalyzed version. Another distinct behavior between the Ni- and Pd-catalyzed allylation was demonstrated in the reaction of hex-1,5-diene-3,4-diol derivatives: the Pd catalyst did not give any coupling product, whereas the Ni-catalyzed InI-mediated reaction with benzaldehyde afforded the 1:1 and 1:2 adduct diols selectively depending on the reaction conditions.

In situ formation of allyl ketones via Hiyama-Nozaki reactions followed by a chromium-mediated Oppenauer oxidation

In Hiyama-Nozaki reactions of allylchromium with aldehydes the expected products are homo-allylalcohols. However, oxidation products derived from these, predominantly allyl ketones, can be common side products. This can be explained by an Oppenauer-(Meerwein-Ponndorf-Verley)-type mechanism (OMPV-reaction). The amount of oxidation is strongly dependent on the substitution pattern of the reaction partners and the reaction conditions. An appropriate choice of these can lead to preferential formation of ketones instead of the alcohols. In addition to its synthetic usefulness, the oxidation-reduction equilibrium is of the utmost importance for the design of enantioselective Hiyama-Nozaki reactions because it is also a potential racemization pathway.

Acid-mediated, chromium-catalyzed allylation of aldehydes

Allyl bromides are efficiently coupled with aryl and aliphatic aldehydes in the presence of manganese metal, collidine hydrochloride, bis(diisopropylphosphino)ethane and chromium dichloride. Homoallylic alcohols are isolated in good to excellent yields directly from the reaction mixture.

Effect of Crown Ethers on the Regioselectivity of Allylation of Benzaldehyde with Allylic Barium Reagents

An increase of α-regioselectivity was observed in the reaction of allylic barium reagents with aldehydes employing crown ether as an additive. For example, an α/γ regioselectivity was improved to 98/2 from 92/8, when an equimolar amount of 18-crown-6 was added to geranylbarium reagent in THF at -78°C prior to the reaction with benzaldehyde.

Barbier-type allylation of aldehydes and ketones: With metallic lead in aqueous media

Homoallylic alcohols can be obtained from allylation of aldehydes and ketones with allyl bromide promoted by metallic lead. These reactions can be carried out smoothly in aqueous media.

Nozaki-Hiyama-Kishi reactions catalytic in chromium

A procedure is described which allows for the first time to perform chromium-catalyzed additions of organic halides to aldehydes ("Nozaki-Hiyama-Kishi reactions"). The reactions are mediated by trimethylchlorosilane, and the active Cr2+ species is constantly recycled by means of nontoxic, commercial manganese powder as the stoichiometric reductant. This method nicely applies to different substituted aryl, heteroaryl, alkynyl, alkenyl, and allyl halides as well as to alkenyl inflates as the starting materials and rivals its stoichiometric precedent in terms of efficiency, practicability, and chemo- and diastereoselectivity. Specifically, it has been demonstrated that the addition of crotyl bromide to various aldehydes is highly stereoconvergent, i.e. the respective anti-configurated homoallyl alcohols are obtained with excellent diastereomeric excess independent of whether the starting halide is (E)- or (Z)-configurated. In accordance with the likely catalytic cycle, both CrCl2(cat.) or CrCl3(cat) turned out to efficiently mediate reactions of this type, with the latter being preferred for practical reasons. Finally, attempts were made to optimize the number of turnovers in chromium. In this context the use of either chromocene (Cp2Cr) or CpCrCl2·THF as "pre-catalysts" were found to significantly upgrade the efficiency of such C-C bond formations, with ≤ 1 mol % of chromium being required in these cases for quantitative conversions.

Chromium(II)-Mediated Stereodivergent Additions of Allylic Phosphates and Halides to Aldehydes

The addition of γ-disubstituted allylchromium(III) reagents to aldehydes proceeds in a stereodivergent manner, in contrast to the case of γ-monosubstituted allylchromium(III) species.The method allows the preparation of a variety of homoallylic alcohols bearing a quaternary center of defined relative configuration in the α-position.The preparation of both stereomeric homoallylic alcohols 13 is possible by using either of the two (E)- or (Z)-allylic precursors.The reaction has been extended to a γ-monosubstituted β-(trimethylsilyl)allylic system.The intermediate allylic chromium(III) reagents can be conveniently prepared from the corresponding phosphates (or chlorides) in DMPU or THF in the presence of catalytic amounts of LiI.