61692-22-6

Upstream product

• 75-77-4 chloro-trimethyl-silane 
• 4096-34-8 cyclohex-3-enone 
• 930-68-7 cyclohexenone 

Downstream Products

• 821775-57-9 (+)-(R)-4-((R)-hydroxy(phenyl)methyl)-2-cyclohexen-1-one 
• 1140920-69-9 (S,R)-methyl 2-hydroxy-2-(4-oxocyclohex-2-en-1-yl)-2-phenylacetate 

Relevant academic research and scientific papers

Lewis base activation of Lewis acids: Catalytic, enantioselective vinylogous aldol addition reactions

(Chemical Equation Presented) The generality of Lewis base catalyzed, Lewis acid mediated, enantioselective vinylogous aldol addition reactions has been investigated. The combination of silicon tetrachloride and chiral phosphoramides is a competent catalyst for highly selective additions of a variety of α,β-unsaturated ketone-, 1,3-diketone-, and α,β- unsaturated amide-derived dienolates to aldehydes. These reactions provided high levels of γ-site selectivity for a variety of substitution patterns on the dienyl unit. Both ketone- and morpholine amide-derived dienol ethers afforded high enantio- and diastereoselectivity in the addition to conjugated aldehydes. Although α,β-unsaturated ketone-derived dienolate did not react with aliphatic aldehydes, α,β-unsaturated amide-derived dienolates underwent addition at reasonable rates affording high yields of vinylogous aldol product. The enantioselectivities achieved with the morpholine derived-dienolate in the addition to aliphatic aldehydes was the highest afforded to date with the silicon tetrachloride-chiral phosphoramide system. Furthermore, the ability to cleanly convert the morpholine amide to a methyl ketone was demonstrated.

Structural investigations into the retro-Diels-alder reaction. Experimental and theoretical studies

The manifestations of the retro-Diels Alder reaction in the ground-state structures of a range of cyclopentadiene and cyclohexadiene cycloadducts 9-15 have been investigated by a combination of techniques. These include low-temperature X-ray crystallography, density functional calculations (B3LYP/6-31G(d,p)) on both the ground states and transition states, and the measurement of 13C-13C coupling constants. We have found that the carbon - carbon bonds (labeled bonds a and b), which break in the rDA, are longer in the cycloadducts 9-15 than in their corresponding saturated analogues 9s-15s, which cannot undergo the rDA reaction. The degree of carbon - carbon bond lengthening appears to be related to the reactivity of the cycloadduct, thus the more reactive benzoquinone cycloadducts 5b and 13 have longer carbon - carbon bonds. Those cycloadducts 14 and 15 which are predicted to undergo asynchronous reactions show differing degrees of carbon - carbon bond lengthening, reflecting the differing degrees of bond breaking at the calculated transition states for the rDA.

Double ring-opening reactions of bis-cyclopropanes promoted by iron salts

Certain bis-cyclopropanes were prepared from the corresponding dienol silane and, on treatment with ferric salts, were found to undergo two sequential C-C bond cleavages to give products corresponding to overall two carbon ring-expansion. In one case the nature of the product obtained was found to depend upon the types of ferric salts employed.

Studies Directed Towards the Total Synthesis of Anticapsin and Related Compounds. II. Diels-Alder Addition of N-Acyl Dehydroalanine Esters to 1-Trimethylsilyloxycyclohexa-1,3-diene

In a study directed towards the total synthesis of anticapsin and related compounds, the Diels-Alder addition of N-acyl dehydroalanine esters (15)-(19) to 1-trimethylsilyloxycyclohexa-1,3-diene (6) was investigated.The cycloadditions were highly regiosele

Efficient Synthesis of Siloxy Dienes from α,β-Unsaturated Ketones

A novel method for the preparation of siloxy dienes has been developed.The reaction system was established by a multivariate screening experiment, where catalysts and solvents were selected according to their principal properties.The best system was lithium bromide-chlorotrimethylsilane-triethylamine in tetrahydrofuran.Optimum experimental conditions were determined by response surface methods.The following substrates were used: 2-butenone, 4-methyl-3-penten-2-one, 4-methoxy-3-buten-2-one, 1-acetylcyclohexene, 2-cyclohexenone, 2-cyclopentenone, 4-phenyl-3-buten-2-one, 4-(4-methoxyphenyl)-3-buten-2-one, and 4,4-dimethyl-2-cyclohexenone.Isolated yields were in the range of 82 - 96percent.

AN APPROACH TO THE SYNTHESIS OF GELSEMINE: THE INTRAMOLECULAR RAECTION OF AN ALLYLSILANE WITH AN ACYLIMINIUM ION FOR THE SYNTHESIS OF ONE OF THE QUATERNARY CENTRES

We describe an efficient synthesis (summarised in Schemes 8 and 10) of an advanced intermediate (34) suitable for the synthesis of gelsemine.The key steps in the synthesis are (i) the Diels-Alder reaction between 1-tetrahydropyranyloxycyclohexa-1,3-diene (10) and methyl β-nitroacrylate (11) giving an adduct (12), in which the chiral centre in the tetrahydropyranyl ring is produced substantially in only one sense, (ii) the rearrangement of a bicyclooctane (23) into a bicyclooctane (24), where control of which bridge migrates is achieved by a choice of the counterion in the Lewis acid, and (iii) the efficient formation of the quaternary centre by an intramolecular reaction between an allylsilane group and an acyliminium ion (33 -> 34).

O-SILYLATED DIENOLATES IN ORGANIC SYNTHESIS: γ-SELECTIVE ALKYLATION OF UNSATURATED CARBONYL COMPOUNDS BY 1,3-DITHIENIUM FLUOROBORATE

The alkylation of O-silylated dienolates of unsaturated aldehydes, ketones, and esters with 1,3-dithienium fluoroborate shows useful γ-selectivity.The γ-products are selectively protected 1,5-dicarbonyl compounds.

DARSTELLUNG UND REAKTIONEN VON TRICARBONYL-(TRIMETHYLSILOXY-1,3-CYCLOHEXADIEN)-EISEN-KOMPLEXEN

Tricarbonyl(trimethylsiloxy-1,3-cyclohexadien)iron complexes, 5 and 6, react with triphenylmethyl tetrafluoroborate by elimination of both, hydride and the trimethylsilyl group, to give 9 and 10.The tricarbonyl(1,3-cyclohexadienyl)iron salt, 11, resulting