Enantioselective cyclopropanation of carboxylic esters with alkyl magnesium bromides in the presence of titanium(IV) (4R,5R)-TADDOLates

Konik, Yulia A.; Kananovich, Dzmitry G.; Kulinkovich, O. G.

doi:10.1016/j.tet.2013.05.118

Cited by 24 publications

(4 citation statements)

References 35 publications

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“…This chemistry is comparable to a report using base, which will be covered in more detail in Section 5. 271 Other similar strategies using protic acid sources, such as other aqueous acid solutions or even aluminum oxide treated with tartaric acid, 272 have been employed successfully to obtain the corresponding ring-opened ketone product.…”

Section: Ring Opening Of Cyclopropyl Alcohols With Brønsted Acidsmentioning

confidence: 99%

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Selective Carbon–Carbon Bond Cleavage of Cyclopropanols

et al. 2020

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The carbon–carbon (C–C) bond cleavage of cyclopropanols is a wide area of research with much current activity. This review highlights new developments in this area over the past two decades. A summary is made of the three main reactivity modes, namely, homoenolate chemistry, β-keto radical chemistry, and acid-catalyzed ring-opening, as well as all other methods for the C–C bond cleavage and functionalization of cyclopropanols, including base-mediated ring-opening, metal-catalyzed C–C insertions and eliminations, oxidative fragmentation using hypervalent iodine reagents, reactions of donor–acceptor cyclopropanols, and pericylic reactions. Emphasis is placed on the synthetic utility of cyclopropanols and related derivatives, which have emerged as unique three-carbon synthons.

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Section: Ring Opening Of Cyclopropyl Alcohols With Brønsted Acidsmentioning

confidence: 99%

“…Other similar strategies using protic acid sources, such as other aqueous acid solutions or even aluminum oxide treated with tartaric acid, have been employed successfully to obtain the corresponding ring-opened ketone product.…”

Section: Acid-mediated Ring Opening Of Cyclopropyl Alcoholsmentioning

confidence: 99%

Selective Carbon–Carbon Bond Cleavage of Cyclopropanols

et al. 2020

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“…This discovery has helped dramatically expand the scope of Kulinkovich reactions, as alkene starting materials are more widely available than Grignard reagents. 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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“…The Corey–Chaykovsky cyclopropanation reaction involves the addition of a sulfur ylide to an enone, generating a transient enolate, which undergoes a subsequent intramolecular cyclization to give the cyclopropane motif. − The second approach relies on the (−)-sparteine-catalyzed asymmetric carbolithiation of cinnamyl derivatives leading, after the 1,3-elimination reaction, to the corresponding trans -cyclopropanes in excellent enantiomeric ratios . As far as the cyclopropanols are concerned, and although cyclopropanation reactions of enol ethers using the Fischer carbene have been reported, the most widely used method relies on the addition of a Grignard reagent to an ester in the presence of a catalytic amount of Ti(O i Pr) 4 (Kulinkovich reaction). − The introduction of a chiral titanium species lead to the formation of chiral cyclopropanols in good enantioselectivity (see Scheme d). The preparation of cyclopropylamines is based on the same conceptual approach from various amides (Scheme e). , The scope of this reaction was later expanded to the use of alkyl and aryl nitriles as suitable candidates in forging the cyclopropylamine motif …”

Section: Introductionmentioning

confidence: 99%

Asymmetric Preparation of Polysubstituted Cyclopropanes Based on Direct Functionalization of Achiral Three-Membered Carbocycles

2018

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In addition to the appealing synthetic transformations that cyclopropanes present, they are also part of larger molecular structures that possess a wide range of biological properties. Therefore, the preparation of enantiomerically enriched cyclopropanes has consistently been a very interesting research topic in organic synthesis. In this Focus Review, we are presenting new methods for the synthesis of these target compounds through catalytic and asymmetric direct functionalization of simple achiral three-membered carbocycle precursors. These convergent and very flexible approaches allow the preparation of a large variety of polysubstituted alkyl-, vinyl-, alkynyl-, and arylcyclopropanes but also cyclopropanols and cyclopropylamines in very high diastereo- and enantiomeric ratios from a single precursor, underlining the power of this synthetic route.

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Enantioselective cyclopropanation of carboxylic esters with alkyl magnesium bromides in the presence of titanium(IV) (4R,5R)-TADDOLates

Cited by 24 publications

References 35 publications

Selective Carbon–Carbon Bond Cleavage of Cyclopropanols

Selective Carbon–Carbon Bond Cleavage of Cyclopropanols

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

Asymmetric Preparation of Polysubstituted Cyclopropanes Based on Direct Functionalization of Achiral Three-Membered Carbocycles

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