24156-95-4

Basic information

• Product Name: 3,5,5-Trimethyl-2-cyclopenten-1-one
• Synonyms: 3,5,5-Trimethyl-2-cyclopenten-1-one
• CAS NO: 24156-95-4
• Molecular Formula: C₈H₁₂O
• Molecular Weight: 124.1803
• Mol File: 24156-95-4.mol

Chemical Properties

• Boiling Point: 173°Cat760mmHg
• Flash Point: 62.1°C
• Appearance: /
• Density: 0.92g/cm³
• Vapor Pressure: 1.29mmHg at 25°C
• Refractive Index: 1.458
• CAS DataBase Reference: 3,5,5-Trimethyl-2-cyclopenten-1-one(CAS DataBase Reference)
• NIST Chemistry Reference: 3,5,5-Trimethyl-2-cyclopenten-1-one(24156-95-4)
• EPA Substance Registry System: 3,5,5-Trimethyl-2-cyclopenten-1-one(24156-95-4)

Safety Data

• Hazardous Substances Data: 24156-95-4(Hazardous Substances Data)

Usage

InChI:InChI=1/C8H12O/c1-6-4-7(9)8(2,3)5-6/h4H,5H2,1-3H3

Upstream product

• 56001-56-0 2,2,4-trimethyl-4-pentenoic acid 
• 74-99-7 prop-1-yne 
• 26308-77-0 2,2,4-trimethyl-3-cyclopentenol 
• 5455-94-7 2,2,5,5-tetramethyltetrahydro-3-oxofuran 
• 3238-16-2 3-chloro-3-methyl-2-butanone oxime 
• 141-97-9 ethyl acetoacetate 
• 64149-44-6 Tetrakis(iodmethyl)2,2,4,4-cyclobutanon 
• 866-71-7 3,3-dimethyl-hexane-2,5-dione 
• 99182-08-8 3-methoxycarbonyl-4,4-dimethylhexane-2,5-dione 
• 169627-05-8 3-Hydroxy-2,2,3-trimethyl-5-oxo-cyclopentanecarboxylic acid methyl ester 
• 142-30-3 2,5-dihydroxy-2,5-dimethyl-3-hexyne 
• 608136-01-2 2,2,4-Trimethyl-4-pentenoic acid chloride 
• 1111-97-3 3-chloro-3-methylbut-1-yne 
• 118768-39-1 2,4,4-trimethyl-5-methylene-4,5-dihydro-3-furoic acid 

Downstream Products

• 28056-54-4 2,2,4-trimethylcyclopentan-1-one 
• 1215117-75-1 4,4,6-trimethyl-3,7-dioxabicyclo[4.1.0]heptan-2-one 
• 101088-54-4 2-benzyl-3,5,5-trimethyl-cyclopent-2-enone 

Relevant articles and documents

Nickel-catalyzed difunctionalization of unactivated alkenes initiated by unstabilized enolates

This report demonstrates the possibility of a nickel-catalyzed difunctionalization of unactivated alkenes initiated by an unstabilized enolate nucleophile. The process tolerates a diverse range of electrophiles, including aryl, heteroaryl, alkenyl, and amino electrophiles. An electron-deficient phosphine ligand and a tetrabutylammonium salt additive were crucial for promoting efficient vicinal difunctionalization.

Alternative synthesis of 2-hydroxy-3,5,5-trimethylcyclopent-2-en-1-one

The 2-hydroxy-3,5,5-trimethylcyclopent-2-en-1-one (1) was synthesized in 42% yield by rearrangement of epoxy ketone 10 on treatment with BF3 ? Et2O under anhydrous conditions. Intermediate 10 was available from the known enone 8, either via direct epoxidation (60% H2O 2 , NaOH, MeOH; yield 50%), or via reduction to the corresponding allylic alcohol 14 (LiAlH4, THF), followed by epoxidation ([VO(acac)2], tBuOOH) and reoxidation under Swern conditions, in 37% total yield.

Total synthesis of (+/-)-cameroonan-7alpha-ol and biomimetic rearrangements to related nopsane sesquiterpenes.

A total synthesis of the novel silphinane sesquiterpene alcohol (+/-)-cameroonanol (6-OH) from bicyclic enone 10 was accomplished by conjugate addition of crotylsilane, photochemical hydrobromination, intramolecular alkylation, and hydride reduction. The stereoisomers cameroonan-7beta-ol (18-OH) and 9-epicamerooonanols (19 and 20) were separated from isomer mixtures and the 9-desmethylcameroonanols (21-OH and 22-OH) were obtained by similar means. Solvolysis of 6-OMs and 18-OMs effected skeletal rearrangements to (+/-)-silphiperfol-6-ene (5), (+/-)-prenopsanol (7) and (+/-)-nopsanol (8), and (+/-)-silphiperfolan-7beta-ol (9) in parallel with biogenetic schemes proposed for these naturally occurring sesquiterpenes. The nor analogues 21-OMs and 22-OMs underwent solvolytic rearrangments to a similar set of nor products. The increase in solvolytic rates for the 7beta-mesylates 18-OMs and 22-OMs in comparison to the 7alpha epimers is attributed to concerted antiperiplanar Wagner-Meerwein rearrangements to the prenopsyl and norprenopsyl carbocations. Further analysis of the kinetic data and comparisons with solvolysis rates for the structurally related silphin-1beta-yl and silphin-1alpha-yl mesylates (28 and 29) are presented. The rearrangements observed afford chemical precedent for the biogenetic pathways in the literature for these silphinane sesquiterpenes.

Synthesis of rac-presilphiperfolan-9-ol

rac-Presilphiperfolan-9-ol (2) and three of its epimers (24, 29, 30) were synthesized by starting from the known 8-hydroxy-3,3,5-trimethylbicyclo[3.3.0]octan-2-one (10). The spectroscopic data of rac-2 are identical with those of the natural (-)-presilphiperfolan-9-ol, previously isolated from Artemisia laciniata. rac-2 has a strong woody, amber odor whereas the 9-epimer 24 smells strongly patchouli-like. VCH Verlagsgesellschaft mbH, 1996.

The chemoselective cyclisation of unsymmetrical γ-diketones to cyclopentenones by ditected aldol reaction using a magnesium chelate

The feasibility of synthesising disubstituted cyclopent-2-enones chemoselectively from unsymmetrical γ-diketones, using an aldol reaction directed by magnesium chelation, has been studied.Treatment of 3,3-dimethylhexane-2,5-dione 15 with aqueous sodium hydroxide (0.5 mol dm-3) gives a mixture of 3,5,5-trimethyl- 12 and 3,4,4-trimethylcyclopent-2-enone 14 in an isomer ratio 2.2:1.Insertion of an α-methoxycarbonyl grouping as a control element allows formation of a magnesium chelate 17 when treated with magnesium methoxide, and the major product is then mainly the undehydrated aldol 21.This, when treated with aqueous sodium hydroxide (0.5 mol dm-3) to dehydrate, hydrolyse and decarboxylate, gives the 3,5,5-trimethyl- and 3,4,4-trimethylcyclopent-2-enones in a nearly chemospecific ratio of 1:49.When 3-methoxycarbonyl-4,4-dimethylhexane-2,5-dione 16 is treated with aqueous sodium hydroxide (0.5 mol dm-3), omitting the magnesium methoxide treatment, the corresponding ratio of cyclopentenones was still an interesting 1:7.3.Treatment with sodium methoxide in methanol gives, by contrast γ-lactone 27.Treatment of undecane-4,7-dione 34 with aqueous sodium hydroxide (0.5 mol dm-3) at reflux gives 2,3-dipropylcyclopent-2-enone 36 and 3-butyl-2-ethylcyclopent-2-enones 35 in a ratio of almost 1:1.Treatment of 6-methoxycarbonylundecane-4,7-dione 33 with magnesium methoxide in methanol gives undehydrated aldol which when treated with aqueous sodium hydroxide gives the dipropylcyclopent-2-enone 36 and 3-butyl-2-ethylcyclopent-2-enones 35 in 9:1 ratio.Conversely, the 5-methoxycarbonyldione 32 gives a corresponding ratio of 36 to 35 of 1:9.The best ratios attained, 1:15 for 36 and 35 from 32 and 20:1 for 36 and 35 from 33, were when magnesium methoxide in refluxing benzene or toluene were employed.There is still a strong chemoselective effect when the magnesium treatment is omitted.Preliminary examination of the corresponding cyclohex-2-enone systems gave poorer chemoselectivities when either procedure was employed. 6-Methoxycarbonyldodecane-5,9-dione 52 gave 2,3-dipropyl-54 and 3-butyl-2-ethyl-cyclohex-2-enone 55 in a ratio of ca. 4:1 whilst the 5-methoxycarbonyldodecane-4,8-dione 53 gave a 1: ca. 4 ratio.

Cyclocarbonylation of acyclic 1,3-dienes via their tricarbonyl iron complexes: Cyclopenten-2-ones and dicarbonyl cyclopentadienyl iron halides

Tricarbonyl iron complexes of acyclic 1,3-dienes can be converted to conjugated cyclopentenones by decomplexation with aluminium halides. Most complexes of simple dienes need drastic conditions for the cyclocarbonylation to occur (100 Atm CO, 100°C), with the exception of 1,1,3-trialkylbutadiene complexes which are nearly quantitatively converted into cyclopentenones at room temperature, even in the absence of a CO atmosphere. Under the same mild conditions, the other complexes lead in modest yields to cyclopentadienyl dicarbonyl iron halides by a cyclocarbonylation reaction followed by an aluminium halide promoted deoxygenation.

Keto ethers. IV. Products formed on reaction of dihydro-2,2,5,5-tetramethyl-3(2H)-furanone with strong acids

Reaction of tetrahydro-2,2,5,5-tetramethyl-3(2H)-furanone (1) with 96 or ca. 100percent sulfuric acid or hot polyphosphoric acid followed by aqueous quenching gave the following products: 2-hydroxy-2,5-dimethyl-4-hexen-3-one (3), 2,4,4-trimethyl-2-cyclopenten-1-one (7), 3,5,5-trimethyl-2-cyclopenten-1-one (8), tetrahydro-2,3,5,5-tetramethylfuran-2,3-diol (11), 2,5-dihydro-3,5,5-trimethyl-2-methylenefuran (17) and its dimer 20, 2,5-dihydro-2,3,5,5-tetramethyl-2-furanol (18), 4-hydroxy-2,4-dimethyl-2-pentenoic acid γ-lactone (22), 2,3,5-trimethyl-2-cyclopenten-1-one (23), and tetramethylfuran (25).In 96percent sulfuric acid the products arise by ring opening, ring opening followed by reclosure to carbocyclic products, methyl migration from C-2 to C-3 to give rearranged furan derivatives, and oxidation.In ca. 100percent sulfuric acid or hot polyphosphoric acid further methyl migrations can occur to give 23 and 25.

Intramolecular Olefinic Aldehyde Prins Reactions for the Construction of Five-Membered Rings

Four catalysts (Me2AlCl SnCl4 > EtAlCl2 > Et2AlCl) for the cyclization of olefinic aldehydes by an internal Prins mechanism have been compared by using systems that afford five-membered rings by type I and type II ene processes.Stannic chloride and Me