Enantioselective and regioselective nickel-catalyzed multicomponent coupling of chiral allenes, aromatic aldehydes, and silanes

Ng, Sze‐Sze; Jamison, Timothy F.

doi:10.1016/j.tet.2005.08.063

Cited by 56 publications

(26 citation statements)

References 52 publications

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“…In this process, enantioenriched alkyl-substituted allenes, aromatic aldehydes, and silanes are coupled by an achiral Ni(NHC)-based catalyst with near perfect transfer of asymmetry 38. Application of this reaction to synthesis will depend on the availability of the requisite enantioenriched allene.…”

Section: Introductionmentioning

confidence: 99%

One-Pot Multicomponent Coupling Methods for the Synthesis of Diastereo- and Enantioenriched (Z)-Trisubstituted Allylic Alcohols

et al. 2009

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Abstract(Z)-Trisubstituted allylic alcohols are widespread structural motifs in natural products and biologically active compounds but are difficult to directly prepare. Introduced herein is a general one-pot multicomponent coupling method for the synthesis of (Z)-α,α,β-trisubstituted allylic alcohols. (Z)-Trisubstituted vinylzinc reagents are formed in situ by initial hydroboration of 1-bromo-1-alkynes. Addition of dialkylzinc reagents induces a 1,2-metallate rearrangement that is followed by a boron-to-zinc transmetallation. The resulting vinylzinc reagents add to a variety of prochiral aldehydes to produce racemic (Z)-trisubstituted allylic alcohols. When enantioenriched aldehyde substrates are employed (Z)-trisubstituted allylic alcohols are isolated with high dr (>20:1 in many cases). For example, vinylation of enantioenriched benzyl protected α-and β-hydroxy propanal derivatives furnished the expected anti-Felkin addition products via chelation control. Surprisingly, silyl protected α-hydroxy aldehydes also afford anti-Felkin addition products. A protocol for the catalytic asymmetric addition of (Z)-trisubstituted vinylzinc reagents to prochiral aldehydes with a (−)-MIB-based catalyst has also been developed. Several additives were investigated as inhibitors of the Lewis acidic alkylzinc halide byproducts, which promote the background reaction to form the racemate. α-Ethyl and α-cyclohexyl (Z)-trisubstituted allylic alcohols can now be synthesized with excellent levels of enantioselectivity in the presence of diamine inhibitors.

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Section: Introductionmentioning

confidence: 99%

One-Pot Multicomponent Coupling Methods for the Synthesis of Diastereo- and Enantioenriched (Z)-Trisubstituted Allylic Alcohols

et al. 2009

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“…The regioselectivity of the initial CÀC bond-forming step in other classes of reductive couplings of allenes has been shown to strongly depend upon the nature and Lewis acidity of the reducing agent. [16][17][18][19] Processes selective for addition to the internal or the terminal carbon atoms of allenes have both been demonstrated in various nickel-catalyzed coupling processes. For example, the extensive developments from Ng and Jamison involving allene-aldehyde reductive coupling reactions, [16] as well as the related allene-CO 2 coupling processes developed by Mori and co-workers, [17] both involve CÀC bond formation at the allene central carbon atom.…”

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confidence: 99%

Regioselective Nickel‐Catalyzed Reductive Couplings of Enones and Allenes

Chen

Montgomery

2010

Angew Chem Int Ed

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“…Hydroamination,1 three-component coupling,2 Pauson–Khand-type cycloaddition,3 and tandem coupling/cyclization4 have all been applied to chiral allenes to give enantiopure products. The addition reactions of carbenes5 and nitrenes6 with allenes have also been employed in stereoselective synthesis.…”

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confidence: 99%

“…Allene (+)- 1d was prepared from an enantiopure (>98% ee) alcohol following a known procedure,2a,15 then subjected to the two-step, one-flask silacyclopropanation/carbonyl insertion reaction to provide oxasilacyclopentane ( R , S )-(−)- 6 in 65% yield. Oxasilacyclopentane (−)- 6 underwent protodesilylation to afford alcohol ( R , S )-(+)- 11 in 75% yield and 96% ee 16.…”

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confidence: 99%

Alkylidenesilacyclopropanes Derived from Allenes: Applications to the Selective Synthesis of Triols and Homoallylic Alcohols

et al. 2009

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Several alkylidenesilacyclopropanes were prepared by silver-mediated silylene transfer to allenes. Oxasilacyclopentanes derived from allenes were prepared with high regio- and diastereoselectivity by a two-step, one-flask silacyclopropanation/carbonyl insertion reaction. Triols and homoallylic alcohols were formed diastereoselectively by functionalizing the oxasilacyclopentanes. An optically active allene (>98% ee) was utilized to synthesize an enantiopure homoallylic alcohol in 96% ee.

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Enantioselective and regioselective nickel-catalyzed multicomponent coupling of chiral allenes, aromatic aldehydes, and silanes

Cited by 56 publications

References 52 publications

One-Pot Multicomponent Coupling Methods for the Synthesis of Diastereo- and Enantioenriched (Z)-Trisubstituted Allylic Alcohols

One-Pot Multicomponent Coupling Methods for the Synthesis of Diastereo- and Enantioenriched (Z)-Trisubstituted Allylic Alcohols

Regioselective Nickel‐Catalyzed Reductive Couplings of Enones and Allenes

Alkylidenesilacyclopropanes Derived from Allenes: Applications to the Selective Synthesis of Triols and Homoallylic Alcohols

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