Reactions d'addition d'organomagnesiens aux alcools α-acetyleniques

Jousseaume, B.; Duboudin, Jean‐Georges

doi:10.1016/s0022-328x(00)91880-1

Cited by 37 publications

(9 citation statements)

References 9 publications

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“…In contrast, only a few reports about the addition of allylic metals to triple bonds are found in the literature . An allyl Grignard reagent adds to propargylic alcohols or homopropargylic alcohols by an anti addition process to give both regioisomers in the absence or in the presence of CuI catalyst . Allylzincation of terminal alkynes is generally complicated by competitive zincation of alkynes and double allylzincation. , Here we report that allylmagnesium bromide adds to the triple bond of the alkyl ether of homopropargylic alcohol to give monoallylated products with high regio- and stereoselectivities in the presence of a catalytic amount of manganese salt such as MnI 2 , Mn(acac) 3 , or Mn 2 (CO) 10 .…”

mentioning

confidence: 73%

Allylmagnesation and Diallylation of Acetylenic Compounds Catalyzed by Manganese Salts

1996

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mentioning

confidence: 73%

Allylmagnesation and Diallylation of Acetylenic Compounds Catalyzed by Manganese Salts

1996

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“…26 Such isomerization is favored by intramolecularly induced chelation of the propargyl OH group to the metal, which shifts the equilibrium toward the thermodynamically more stable anti-intermediate prior to the protodemetalation step. 27 Unlike the above method based on thermodynamic control, the Carretero research team devised an alternative strategy for reversing the stereoselectivity of the Pd-catalyzed hydroarylation of unsymmetrical dialkyl alkynes with boronic acids (Scheme 8). 28 A stereodivergent approach was designed that enables the access to unconventional anti-addition products by merging, in a tandem fashion, an initial thermodynamically favored an E-selective Pd-catalyzed syn-hydroarylation with arylboronic acids, with a kinetically controlled Ir-photocatalyzed E → Z photoisomerization (see the mechanistic discussion below).…”

Section: Hydroarylation Of Internal Alkynesmentioning

confidence: 99%

Transition-Metal-Catalyzed Functionalization of Alkynes with Organoboron Reagents: New Trends, Mechanistic Insights, and Applications

et al. 2021

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Catalytic functionalization of alkynes with organoboron reagents provides a straightforward access to stereochemically defined multisubstituted alkenes, which are structural motifs commonly found in bioactive compounds and organic materials. Recent progress has substantially broadened the scope of this field on several fronts. Strategies for regioselectivity control in the 1,2-migratory insertion across unsymmetrical internal alkynes, as well as for the direct access to products with anti-insertion stereochemistry, have been devised. The alkenyl-to-aryl 1,4-metal migration upon metal insertion has been recently exploited in powerful cascade sequences leading to complex polycyclic scaffolds, including the development of enantioselective processes. Elegant enantiospecific and dynamic kinetic resolution methods have been developed for accessing chiral allenes from propargylic alcohol derivatives. Mechanistic manifolds have emerged based on single-electron transfer (SET) that have provided a fresh impetus for alkyne 1,2-difunctionalization with complementary stereoselectivity to processes relying on 1,2-insertion of R–M species. Herein, we discuss the most recent advances in transition-metal-catalyzed functionalization of alkynes using organoboron reagents, categorized according to the type of mechanistic outcome. Emphasis is placed on mechanistic aspects, synthetic utility, limitations, and challenges for future research.

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“…Similarly, alkyne hydromagnesiation and carbomagnesiation with Grignard reagents delivered trisubstituted allylic alcohols regio-and stereoselectively. [6,7] Although alkyne functionalization through hydrometalation and carbometalation remains at the forefront of research, [3][4][5][6][7] the development of equivalent transformations that avoid stoichiometric metal reagents is clearly desirable. Conversely, whereas related nickel-catalyzed alkyne-carbonyl reductive couplings can be highly regioselective, such processes require terminal reductants that are metallic, pyrophoric, or highly mass intensive (e.g.…”

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confidence: 99%

Divergent Regioselectivity in the Synthesis of Trisubstituted Allylic Alcohols by Nickel‐ and Ruthenium‐Catalyzed Alkyne Hydrohydroxymethylation with Formaldehyde

et al. 2011

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Dedicated to Professor Barry M. Trost on the occasion of his 70th birthday.Trisubstituted allylic alcohols [1,2] are ubiquitous in natural products and are readily converted into diverse chiral building blocks by enantioselective epoxidation, [2a,b] cyclopropanation, [2a,c] hydrogenation, [2a,d] and allylic substitution. [2a,e] Among methods for the regio-and stereoselective synthesis of trisubstituted primary allylic alcohols, alkyne hydrometalation or carbometalation mediated by stoichiometric organometallic reagents has found broad use. [3][4][5][6][7] For example, in seminal studies by Corey et al. (1967), [4c] the regio-and stereoselective hydroalumination of propargyl alcohols was used to construct vinyl iodides, which were converted into trisubstituted allylic alcohols upon exposure to lithium dialkyl cuprates. Similarly, alkyne hydromagnesiation and carbomagnesiation with Grignard reagents delivered trisubstituted allylic alcohols regio-and stereoselectively. [6,7] Although alkyne functionalization through hydrometalation and carbometalation remains at the forefront of research, [3][4][5][6][7] the development of equivalent transformations that avoid stoichiometric metal reagents is clearly desirable. Conversely, whereas related nickel-catalyzed alkyne-carbonyl reductive couplings can be highly regioselective, such processes require terminal reductants that are metallic, pyrophoric, or highly mass intensive (e.g. ZnR 2 , BEt 3 , HSiR 3 ; Scheme 1), [8][9][10] although nickel-catalyzed alcoholmediated alkyne-enone couplings were recently disclosed. [11] Hence, the discovery of alkyne-carbonyl (or alkyneimine) reductive couplings under hydrogenation conditions is significant. [12,13] More recently, an alkyne-carbonyl reductive coupling by ruthenium-catalyzed transfer hydrogenation was developed; however, regioselectivity in such processes remains largely unexplored. [14,15] Herein, we report the regio-and stereoselective synthesis of trisubstituted primary allylic alcohols from alkynes in the absence of stoichiometric metallic reagents. In this reaction, paraformaldehyde is used as a C 1 feedstock and, more remarkably, as a reductant under conditions of transfer hydrogenation with nickel and ruthenium catalysts, which exhibit complementary regioselectivity (Scheme 2).In response to the lack of efficient methods for diene hydroformylation, [16] we recently developed a process for diene hydrohydroxymethylation under the conditions of ruthenium-catalyzed transfer hydrogenation using paraformaldehyde as a C1 feedstock; [17] paraformaldehyde was itself prepared from synthesis gas (via methanol). As the development of efficient catalysts for alkyne hydroformylation remains an unmet challenge, [18] we undertook the current investigation into alkyne-paraformaldehyde reductive coupling. Initial studies focused on the reductive coupling of 1-phenylpropyne (1 a) with paraformaldehyde. We explored the nickel-catalyzed reductive coupling of 1 a with paraformaldehyde in the absence of a reducing agent. [8][9][10] Re...

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Reactions d'addition d'organomagnesiens aux alcools α-acetyleniques

Cited by 37 publications

References 9 publications

Allylmagnesation and Diallylation of Acetylenic Compounds Catalyzed by Manganese Salts

Allylmagnesation and Diallylation of Acetylenic Compounds Catalyzed by Manganese Salts

Transition-Metal-Catalyzed Functionalization of Alkynes with Organoboron Reagents: New Trends, Mechanistic Insights, and Applications

Divergent Regioselectivity in the Synthesis of Trisubstituted Allylic Alcohols by Nickel‐ and Ruthenium‐Catalyzed Alkyne Hydrohydroxymethylation with Formaldehyde

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