23957-85-9

Upstream product

• 606495-09-4 2,6,10-trimethyl-undeca-5,9-dienoic acid 
• 23957-89-3 1-diazo-3,7,11-trimethyl-dodeca-6,10-dien-2-one 
• 20088-48-6 Sesquicaran-2-on 
• 86958-30-7 5-Bromoethynyl-3,3-dimethyl-3H-pyrazole 
• 130921-31-2 (1R,6S,7S)-7-(4-Hydroxy-4-methyl-pentyl)-3,7-dimethyl-bicyclo[4.1.0]heptan-3-ol 
• 130921-30-1 C₁₆H₂₈O₃ 
• 130921-40-3 (1R,6S,7S)-7-(4-Hydroxy-4-methyl-pentyl)-7-methyl-bicyclo[4.1.0]heptan-3-one 
• 130921-27-6 7-Bromo-7-(4-methyl-pent-3-en-1-ynyl)-bicyclo[4.1.0]heptan-3-one 

Relevant academic research and scientific papers

CONVERGENT SYNTHESES IN THE SESQUICARENE SERIES USING A C7-VINYLALKINYLCARBENE

The possibility of achieving convergent syntheses with elaborate carbenes is illustrated by the isobutenylalkynylcarbene II (R = Br).By reaction with 3-cyclohexen-1-one, the endo cyclopropanic adduct IIIa is formed as a major product.Metalation with MeLi, followed by reaction with MeI, proceeds with inversion of configuration ( -> sesquicarene skeleton, XI), or, after protection of the ketofunction, with retention of configuration ( -> isosesquicarene VIII).

Platinum- and gold-catalyzed rearrangement reactions of propargyl acetates: Total syntheses of (-)-α-cubebene, (-)-cubebol, sesquicarene and related terpenes

Propargyl acetates, in the presence of catalytic amounts of late transition-metal salts such as PtCl2 or AuCl3, represent synthetic equivalents of α-diazoketones. This notion is corroborated by a concise approach to various sesquiterpene natural products starting from readily available substrates. Specifically, (+)-carvomenthone (17) is converted into propargyl acetate (S)-26 by a sequence involving Stille cross-coupling of its kinetic enol triflate 18, regioselective hydroboration/oxidation of the resulting 1,3-diene 19, and addition of an alkynyl cerium reagent to aldehyde 21 thus obtained. Since the latter step was found to be unselective, the configuration of the reacting propargyl acetate was unambiguously set by oxidation followed by diastereoselective transfer hydrogenation by using Noyori's catalyst 25. Compound (5)-26, on treatment with PtCl2 in toluene, converted exclusively to the tricyclic enol acetate 27, which was sap onified to give norcubebone 11 in excellent overall yield. The conversion of this compound into the sesquiterpene alcohol (-)-cubebol (6) was best achieved with MeCeCl2 as the nucleophile, whereas the formation-of the parent hydrocarbon (-)-α-cubebene (4) was effected in excellent yield by recourse to iron-catalyzed cross coupling methodology developed in this laboratory. Since norketone 11 has previously been transformed into (-)-β-cubebene (5) as well as (-)-4-epicubebol 8, our approach constitutes formal total syntheses of these additional natural products as well. Along similar lines, the readily available propargyl acetates 1, 33 and 47 were shown to give access to 2-carene 44, sesquicarene 39, and episesquicarene 51 in excellent overall yields. In this series, however, the cy cloisomerization reaction was best achieved with catalytic amounts of AuCl3 in 1,2-dichloroethane as the solvent. In addition to these preparative results, our data provide some insight into the mechanism of these remarkable skeletal rearrangement reactions. Transformations of this type are likely triggered by initial coordination of the alkyne unit of the substrate to the carbophilic transition-metal cation. Formal attack of the alkene moiety onto the resulting π-complex engenders the formation of an electrophilic cyclopropyl carbene species which subsequently reacts with the adjacent acetate unit to give the final product. The alternative phasing of events, implying initial attack of the acetate (rather than the alkene moiety) onto the metal-alkyne complex, is inconsistent with the stereochemioal data obtained during this total synthesis campaign.

Intramolecular cyclopropanation reactions of organozinc carbenoids derived from terpenoid enals

Treatment of a series of unsaturated terpenoid enals with 1,2 bis (chlorodimethylsilyl) ethane and zinc provides a simple and efficient method for intramolecular cyclopropanation.

Rearrangement Approaches to Cyclic Skeletons. I. Photochemical Rearrangement Approaches to (+/-)-Sesquicarene and (+/-)-Sirenin, Fused-Ring Sesquiterpenes

The 4-alkyl, 4-alkenyl, and 4-aryl derivatives of bicyclonona-3,6-dien-2-one (9) were prepared from 9 itself by ultrasound-promoted Barbier reaction followed by PCC oxidation.Photochemical transformation of the 4-(4-methyl-3-pentenyl) derivative of 9, namely 13, in the THF-water gave endo-7-hept-2-ene>acetic acid (14).Acid 14 was converted into endo-7-methyl-exo-7-(4-methyl-3-pentenyl)bicycloheptan-2-one (4), a key intermediate of (+/-)-sesquicarene and (+/-)sirenin total syntheses.Futhermore, a highly stereospecific total synthesis of (+/-)-sesquicarene was acomplished by the photochemical transformation of the 1-methyl derivative of 13 prepared from 2-methyl tropone.

Rearrangement Approaches to Cyclic Skeletons. II. Structural Revision and Total Synthesis of (+/-)-Isosesquicarene, a Fused-Ring Sesquiterpene

The exo-7-(4-methyl-3-pentenyl)derivative of 3-carene(1a), the original structure reported for (+/-)-isosesquicarene, was synthesized starting from tropone, and it was found that 1a is not identical with natural isosesquicarene.The structure of isosesquic

A Novel Synthesis of (+/-)-Sesquicarene

A highly stereospecific total synthesis of (+/-)-sesquicarene was accomplished by the photochemical transformation of the bicyclonona-3,6-dien-2-one (7), which was derived from 2-methyltropone (5), into the bicyclohept-2-ene (3).