Stereoselective synthesis of α-methyl and α-alkyl ketones from esters and alkenes<i>via</i>cyclopropanol intermediates

Barysevich, Maryia V.; Kazlova, Volha V.; Kukel, Aliaksandr G; Liubina, Aliaksandra I.; Hurski, Alaksiej L.; Жабинский, В. Н.; Хрипач, В. А.

doi:10.1039/c8cc00888d

Cited by 18 publications

(7 citation statements)

References 37 publications

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“…The Kulinkovich cyclopropanation has an intrinsic diastereoselectivity for the cis-1,2-dialkylated cyclopropanol when using Grignard reagents larger than ethyl, and the use of chiral TADDOL (a,a,a’,a’-tetraaryl-2,2-disubstituted-1,3-dioxolane-4,5-dimethanol) ligands has allowed for good enantioselectivity 88,101,102 . This diastereoselectivity can be reversed when cyclopropanating homoallylic alcohols as a result of coordinating directing group effects 99 or remote stereocentre influences 103 .…”

Section: Reductive Coupling Reactionsmentioning

confidence: 99%

Modern applications of low-valent early transition metals in synthesis and catalysis

et al. 2018

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Low-valent early transition metals are often intrinsically highly reactive as a result of their strong propensity toward oxidation to more stable high-valent states. Harnessing these highly reducing complexes for productive reactivity is potentially powerful for C-C bond construction, organic reductions, small-molecule activation and many other reactions that offer orthogonal chemoselectivity and/or regioselectivity patterns to processes promoted by late transition metals. Recent years have seen many exciting new applications of low-valent metals through building new catalytic and/or multicomponent reaction manifolds out of classical reactivity patterns. In this Review, we survey new methods that employ early transition metals and invoke low-valent precursors or intermediates in order to identify common themes and strategies in synthesis and catalysis.

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Section: Reductive Coupling Reactionsmentioning

confidence: 99%

Modern applications of low-valent early transition metals in synthesis and catalysis

et al. 2018

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“…Since 144 is prepared from the corresponding ketone through a Simmons–Smith reaction sequence, this overall transformation can be envisioned as a selective monomethylation of a ketone. This isomerization can also be performed using catalytic iridium or stoichiometric magnesium . Ring‐opening is selective for generating the least‐substituted, less anionic homoenolate.…”

Section: Homoenolates As Nucleophilic Reagentsmentioning

confidence: 99%

Modern Developments in the Chemistry of Homoenolates

Mills

Rousseaux

2018

Eur J Org Chem

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Homoenolates are unique synthetic intermediates which display umpolung reactivity. Homoenolates and homoenolate equivalents like cyclopropanols have seen a recent surge in popularity due to their particular utility for accessing β‐functionalized carbonyl derivatives. This popularity has been enabled by the development of protocols for facile access to cyclopropanols and homoenolates from a variety of readily available starting materials. This microreview will highlight common strategies for generating cyclopropanols and metal homoenolates, as well as procedures for homoenolate functionalization, with a particular emphasis on protocols that have appeared after 2003. As an amphoteric molecule, two main reactivity modes have been established: the homoenolate reacts as a carbon nucleophile for β‐functionalization reactions and/or as a carbonyl electrophile, a strategy which has only emerged in the past few years. This microreview will highlight the use of homoenolates as convenient intermediates for accessing especially challenging motifs. The use of homoenolate chemistry in the context of natural product and pharmaceutical synthesis will also be presented.

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“…In all cases the selectivity of the ring opening is controlled by the formation of a primary organometallic species. Regioselective ring opening of cyclopropanols was used to replace the natural C20 methyl group with bulkier substituents to decrease undesired side effects of vitamin D derivatives . The reaction of a ketone having a leaving group at the α-position with bis(iodozincio)methane affords a zinc alkoxide of cyclopropanol.…”

Section: Metal-mediated Ring Cleavagementioning

confidence: 99%

“…Regioselective ring opening of cyclopropanols was used to replace the natural C20 methyl group with bulkier substituents to decrease undesired side effects of vitamin D derivatives. 88 The reaction of a ketone having a leaving group at the α-position with bis(iodozincio)methane affords a zinc alkoxide of cyclopropanol. The reaction proceeds by nucleophilic addition of the dizinc to the carbonyl group and a sequential intramolecular nucleophilic substitution.…”

Section: Ring Cleavage By β-Carbon Eliminationmentioning

confidence: 99%

Creating Stereocenters within Acyclic Systems by C–C Bond Cleavage of Cyclopropanes

2020

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Recent developments in the stereoselective synthesis of polysubstituted cyclopropanes nowadays allow chemists to easily access these strained rings with high diastereo-and enantiomeric ratios. In turn, this development has created a paradigm shift for the synthesis of stereodefined acyclic molecules though selective carbon−carbon bond cleavage. Through chosen illustrative examples, we aim to show in this review that the cleavage of cyclopropane is a powerful approach to reveal sp 3 stereocenters in acyclic systems. The application of these concepts was illustrated by the total syntheses of several natural products and other important molecules, further showing the power of these strategies as a powerful tool in organic synthesis.

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Stereoselective synthesis of α-methyl and α-alkyl ketones from esters and alkenesviacyclopropanol intermediates

Cited by 18 publications

References 37 publications

Modern applications of low-valent early transition metals in synthesis and catalysis

Modern applications of low-valent early transition metals in synthesis and catalysis

Modern Developments in the Chemistry of Homoenolates

Creating Stereocenters within Acyclic Systems by C–C Bond Cleavage of Cyclopropanes

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