Preparation of (S)-2-Allyl-2-Methylcyclohexanone

doi:10.15227/orgsyn.086.0194

Cited by 27 publications

(4 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…reductive elimination) is a lower-energy pathway than the corresponding external mechanism involving attack of the enolate onto an η 3 -allyl complex; it was later discovered that η 1 -allylpalladium carboxylate 5 was found to be the resting state of the catalyst and that decarboxylation was likely rate-limiting. 15,16,17 The lowest-energy pathway for carbon–carbon bond formation occurs through a seven-membered, Claisen-like transition state ( 6 ) similar to that originally proposed by Echavarren, 18 in which the chiral ligand imparts facial selectivity of the allylic alkylation. The sigmatropic character of the transition state likely accounts for the high efficiency with which these sterically hindered quaternary centers are formed, as sigmatropic rearrangements remain a preeminent method for their construction.…”

Section: Stereoablative Transformationsmentioning

confidence: 75%

Advances in Stereoconvergent Catalysis from 2005 to 2015: Transition-Metal-Mediated Stereoablative Reactions, Dynamic Kinetic Resolutions, and Dynamic Kinetic Asymmetric Transformations

et al. 2017

View full text Add to dashboard Cite

An important subset of asymmetric synthesis is dynamic kinetic resolution, dynamic kinetic asymmetric processes and stereoablative transformations. Initially, only enzymes were known to catalyze dynamic kinetic processes but recently various synthetic catalysts have been developed. This review summarizes major advances in non-enzymatic, transition metal promoted dynamic asymmetric transformations reported between 2005 and 2015.

show abstract

Section: Stereoablative Transformationsmentioning

confidence: 75%

Advances in Stereoconvergent Catalysis from 2005 to 2015: Transition-Metal-Mediated Stereoablative Reactions, Dynamic Kinetic Resolutions, and Dynamic Kinetic Asymmetric Transformations

et al. 2017

View full text Add to dashboard Cite

show abstract

“…In our initial experiments, we found that exposure of β-ketoester (±)- 1a 28 to catalytic amounts of [Pd 2 (dba) 3 ] (dba = dibenzylideneacetone) and ( S )- t -BuPHOX ( L1 , PHOX = phosphinooxazoline)29 in the presence of electrophile 2a indeed followed the desired reaction pathway, efficiently producing diastereomers 3a and 4a (82% conversion), albeit with moderate diastereomeric ratio and enantiomeric excess (1:3.1 dr, 42% and 63% ee; see supporting information for details). Following careful optimisation, the combination of an electronically modified PHOX ligand ( L2 , 12.5 mol%)30 and [Pd 2 (dba) 3 ] (5 mol%) in 1,4-dioxane at 40 °C was found to produce diastereomers in high enantioselectivity.…”

Section: Resultsmentioning

confidence: 98%

A palladium-catalysed enolate alkylation cascade for the formation of adjacent quaternary and tertiary stereocentres

et al. 2010

View full text Add to dashboard Cite

The catalytic enantioselective synthesis of densely functionalised organic molecules containing all-carbon quaternary stereocentres is a challenge to modern chemical methodology research. The catalytically controlled asymmetric α-alkylation of ketones represents another difficult task and has been of major interest to our and other research groups in the past. We now report a palladium-catalyzed enantioselective process that addresses both problems at once and allows the installation of vicinal all-carbon quaternary and tertiary stereocentres at the α-carbon of a ketone in a single step. This multiple bond forming process is carried out on readily available β-ketoester starting materials and proceeds via conjugate addition of an in situ-generated palladium enolate to activated Michael acceptors. In other words, the CO2-moiety of the substrate is displaced by a C-C fragment in an asymmetric cut-and-paste reaction. The products are obtained in high yield, diastereomeric ratio, and enantiomeric excess.

show abstract

“… [23] Diacetate 24 was subjected to enzymatic desymmetrization [24] in excellent yield and ee , followed by silyl protection giving 14 . Cyclohexanone 27 was prepared according to the method developed by the Stoltz laboratory from allyl cyclohexanone 13 , [25] which was protected and subjected to hydroboration/oxidation to deliver 26 . Omission of the protection of the ketone in 13 led to the formation of the corresponding hemiacetal.…”

Section: Resultsmentioning

confidence: 99%

Total Synthesis of the Alleged Structure of Crenarchaeol Enables Structure Revision**

et al. 2021

View full text Add to dashboard Cite

Crenarchaeol is a glycerol dialkyl glycerol tetraether lipid produced exclusively in Archaea of the phylum Thaumarchaeota. This membrane-spanning lipid is undoubtedly the structurally most sophisticated of all known archaeal lipids and an iconic molecule in organic geochemistry. The 66-membered macrocycle possesses a unique chemical structure featuring 22 mostly remote stereocenters, and a cyclohexane ring connected by a single bond to a cyclopentane ring. Herein we report the first total synthesis of the proposed structure of crenarchaeol. Comparison with natural crenarchaeol allowed us to propose a revised structure of crenarchaeol, wherein one of the 22 stereocenters is inverted.

show abstract

Preparation of (S)-2-Allyl-2-Methylcyclohexanone

Cited by 27 publications

References 59 publications

Advances in Stereoconvergent Catalysis from 2005 to 2015: Transition-Metal-Mediated Stereoablative Reactions, Dynamic Kinetic Resolutions, and Dynamic Kinetic Asymmetric Transformations

Advances in Stereoconvergent Catalysis from 2005 to 2015: Transition-Metal-Mediated Stereoablative Reactions, Dynamic Kinetic Resolutions, and Dynamic Kinetic Asymmetric Transformations

A palladium-catalysed enolate alkylation cascade for the formation of adjacent quaternary and tertiary stereocentres

Total Synthesis of the Alleged Structure of Crenarchaeol Enables Structure Revision**

Contact Info

Product

Resources

About