Stereoselective Synthesis of Tetrasubstituted Olefins through a Halogen‐Induced 1,2‐Silyl Migration

Barczak, Nicholas T.; Rooke, Douglas A.; Menard, Zachary A.; Ferreira, Eric M.

doi:10.1002/ange.201303007

Cited by 15 publications

(6 citation statements)

References 55 publications

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“…Platform synthesis is a powerful strategy to realize the synthesis of complex molecules in a programable and diversity-oriented format. In this regard, the advances of metal catalysis have inspired tremendous efforts towards modular tetraarylethene construction starting from alkenes [11][12][13][14][15][16][17] or alkynes [18][19][20][21][22][23][24][25][26] . Nevertheless, lengthy synthetic operations, the poor functional group tolerance arising from the participation of organolithium or Grignard reagents, and the often-encountered poor regioselectivity strongly limits their practical application.…”

mentioning

confidence: 99%

Regio- and stereoselective synthesis of tetra- and triarylethenes by N-methylimidodiacetyl boron-directed palladium-catalysed three-component coupling

Lin

Schäfers

et al. 2019

Commun Chem

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The flexible synthesis of tetra-and triarylethenes bearing different aryl groups has been a long-standing challenge in organic synthesis. Here we report a palladium-catalysed syndiarylation of arylethynyl N-methyliminodiacetyl (MIDA) boronates. The products, triarylalkenyl N-methyliminodiacetyl boronates, allow a step-economic and modular synthesis of tetra-or triarylethenes via a subsequent stereospecific Suzuki-Miyaura coupling reaction or base-promoted protodeborylation, respectively. Use of the sp 3-B(MIDA) masked aryl alkyne is the key factor for success by offering an exceptionally good regioselectivity for the boronretentive coupling. The unusual regioselectivity is believed to arise from the stabilization due to the strong electron donation from the C−Pd σ bond to the p-orbital of boron in the transition state of migratory insertion. A broad range of differently substituted tetra-and triarylethenes are constructed in good yields and geometrical control. Synthetic manipulation of the C-B bond also enables the facile construction of several other types of tetra-substituted alkenes.

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mentioning

confidence: 99%

Regio- and stereoselective synthesis of tetra- and triarylethenes by N-methylimidodiacetyl boron-directed palladium-catalysed three-component coupling

Lin

Schäfers

et al. 2019

Commun Chem

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“…Various roles of silver carboxylate AgCOOR salts in such reactions have been proposed: (1) they serve as a source of carboxylate for the Pd(II) metal-centre, participating in carboxylate-assisted concerted metalation deprotonation (CMD) in the C-H activation step; [35][36][37][38][39] (2) they act as a terminal oxidant to regenerate Pd(II) catalyst; [40][41][42] (3) they form heterometallic Pd−Ag complexes that facilitate C−H activation; 40,43,44 (4) they directly activate C−H bond forming Ag-C intermediate; 45,46 (5) they act as halide scavengers in PdX (X = halide) complex after the reductive elimination step. 47 The experimental work to establish the exact role of these silver additives are rare and an understanding of their exact roles in the mechanistic picture is rather incomplete.…”

Section: Role Of Silver Acetate Additivementioning

confidence: 99%

“…Silver carboxylates are known to exist in dimeric form. [47][48][49][50] We computed the energy differences in the thermodynamic stabilities of both the monomeric and dimeric form of silver acetate and found that the dimeric form [AgOAc] 2 is more stable; the formation of [AgOAc] 2 from AgOAc monomers is -16.7 (-19.9) kcal mol -1 downhill. This enhanced stability in the dimer has been attributed to Ag-Ag interactions.…”

Section: Role Of Silver Acetate Additivementioning

confidence: 99%

Alkyne Linchpin Strategy for Drug:Pharmacophore Conjugation: Experimental and Computational Realization of a Meta-Selective Inverse Sonogashira Coupling

et al. 2020

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General consideration S3 Experimental section S3 2.1 Preparation of starting materials S3 -S11 2.2 Optimization details for meta-CH alkynylation with (bromoethynyl)triisopropylsilane Screening of scaffolds S12 -S19 S20 2.3 2.3.1.a 2.3.1.b 2.3.1.c 2.3.1.d General procedure for palladium catalyzed meta-selective CH alkynylation of arene General procedure for palladium catalyzed meta-selective sequential hetero difunctionalization of arene General procedure for gram scale synthesis of meta-alkynylated protocol General procedure for directing group removal of meta-alkynylated protocol General procedure for different application of meta-alkynylated product S20 S21-S22 S23 S23 S24-S25 2.4 Characterization data of meta-alkynylated products S25 -S60 2.5 Mechanistic studies S60 -S66 2.6 Computational methods S67 -S115 References S115 -S122 NMR spectra S123 -S205S10 TBDMSO Br Ph ((1-(bromoethynyl)-4-phenylcyclohexyl)oxy)(tert-butyl)dimethylsilane: 1 H NMR (400 MHz, CDCl 3 ) δ 7.33 (t,

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“…In addition, gold‐catalyzed reactions of propargylic acetates to give α ‐haloenones have been described 9. Recently, a number of synthetic approaches have been reported for β‐haloenones, such as the Brønsted acid‐promoted cyclization of 1‐siloxy‐1,5‐diynes10 and halogen‐induced 1,2‐silyl migration reaction 11. Importantly, the 3‐step synthetic route to α,β‐dihaloenones from cyclohexane‐1,3‐dione using very toxic chlorine and phosgene has been reported 12.…”

Section: Introductionmentioning

confidence: 99%

Ruthenium(II)‐Catalyzed Protocol for Preparation of Diverse α,β‐ and β,β‐Dihaloenones from Diazodicarbonyls

Magar

Lee

2014

Adv Synth Catal

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Efficient one-step syntheses of a,b-and b,b-dihaloenones were achieved by ruthenium(II)catalyzed reactions between cyclic or acyclic diazodicarbonyl compounds and oxalyl chloride or oxalyl bromide in moderate to good yields. This methodology offers several significant advantages, which include ease of handling, mild reaction conditions, one-step reaction, and the use of an effective and non-toxic catalyst. The synthesized compounds were further transformed into highly functionalized novel molecules bearing aromatic rings on the enone moiety using the Suzuki reaction. Scheme 1. Recently reported a,a-chlorination and a,a-fluorination reactions starting from diazo compounds. Scheme 2.Table 1. Cyclic diazodicarbonyl compounds 1a-1s and acyclic diazodicarbonyl compounds 1t-1w.

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Stereoselective Synthesis of Tetrasubstituted Olefins through a Halogen‐Induced 1,2‐Silyl Migration

Cited by 15 publications

References 55 publications

Regio- and stereoselective synthesis of tetra- and triarylethenes by N-methylimidodiacetyl boron-directed palladium-catalysed three-component coupling

Regio- and stereoselective synthesis of tetra- and triarylethenes by N-methylimidodiacetyl boron-directed palladium-catalysed three-component coupling

Alkyne Linchpin Strategy for Drug:Pharmacophore Conjugation: Experimental and Computational Realization of a Meta-Selective Inverse Sonogashira Coupling

Ruthenium(II)‐Catalyzed Protocol for Preparation of Diverse α,β‐ and β,β‐Dihaloenones from Diazodicarbonyls

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