Synthesis and resolution of 2,2'-bis-diphenylphosphino [3,3']biindolyl ; a new atropisomeric ligand for transition metal catalysis

Berens, Ulrich; Brown, John M.; Long, James; Selke, Rüdiger

doi:10.1016/0957-4166(95)00447-5

Cited by 117 publications

(33 citation statements)

References 37 publications

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“…[7] P-Phos (4) [8] is ab ipyridyl. In contrast, the diphosphanes 5-14 are non-benzenoid biheteroaryls.T hey comprise 3,3'-bithiophenyl 5, [9] 3,3'-biindolyl 6, [10] 3,3'-bi(benzothiophenyl) 8, [11] 3,3'-bi(naphthofuryl) 9, [12] 2,2'-bi(benzoimidazolyl) 10, [13] and the 2,2'-biindolyls 11, [14] 12, [14] and 13. [13] Thei someric 2,2'biindolyldiphosphanes 11 [14] and 13 [13] exemplify that certain bi(heteroaryls) may be phosphorylated in more manners than their isocyclic counterparts.T he 3,3'-bi(benzofuryl) 7 [11] is another bi(heteroaryl)-based diphosphane but not aw orthwhile one because it atropisomerizes [15] too easily.…”

Section: Enantiomericallypurediphosphanesarewidelyusedligandsmentioning

confidence: 99%

Atropselective Dibrominations of a 1,1′‐Disubstituted 2,2′‐Biindolyl with Diverging Point‐to‐Axial Asymmetric Inductions. Deriving 2,2′‐Biindolyl‐3,3′‐diphosphane Ligands for Asymmetric Catalysis

Baumann

Brückner

2019

Angew Chem Int Ed

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On the 1 HNMR timescale,2,2'-biindolyls with (R)configured (1-alkoxyprop)-2-yl, (1-hydroxyprop)-2-yl, or (1siloxyprop)-2-yl substituents at C-1 and C-1' are atropisomerically stable at < 0 8 8Ca nd interconvert at > 30 8 8C. A2 ,2'biindolyl (R,R)-17 a of that kind and achiral (!)b rominating reagents gave the atropisomerically stable 3,3'-dibromobiindolyls (M)-and/or (P)-18 a at best atropselectively-because of point-to-axial asymmetric inductions-and atropdivergently,e xhibiting up to 95 %( M)-and as much (P)-atropselectivity.This route to atropisomerically pure biaryls is novel and should extend to other substrates and/or different functionalizations.T he dibromobiindolyls (M)-and (P)-18 a furnished the biindolyldiphosphanes (M)-and (P)-14 without atropisomerization. These syntheses did not require the resolution of ar acemic mixture,w hich distinguishes them from virtually all biaryldiphosphane syntheses knowntodate. (M)-and (P)-14 acted as ligands in catalytic asymmetric allylations and hydrogenations.R emarkably,t he b-ketoester rac-25 c was hydrogenated trans-selectively with 98 %e e; this included adynamic kinetic resolution.

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Section: Enantiomericallypurediphosphanesarewidelyusedligandsmentioning

confidence: 99%

Atropselective Dibrominations of a 1,1′‐Disubstituted 2,2′‐Biindolyl with Diverging Point‐to‐Axial Asymmetric Inductions. Deriving 2,2′‐Biindolyl‐3,3′‐diphosphane Ligands for Asymmetric Catalysis

Baumann

Brückner

2019

Angew Chem Int Ed

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“…7, R'' = CC, Scheme 2). [20] Our previous studies resulted in levels of diastereoselectivity that were similar to those seen with 1, therefore we were surprised when the reaction of bis(thioindole) 11 [21] with 2 gave 12 in relatively high diastereoselectivity (Scheme 3). We became intrigued by the generation of 12 and decided to examine the reaction in more detail by exploring the effect of thioindole substitution on diastereoselectivity.…”

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confidence: 92%

Highly Diastereoselective Sulfonium Ylide Rearrangements to Quaternary Substituted Indolines

2008

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The stereoselective generation of quaternary centers, including quaternary centers at C3 of oxindoles and indolines, remains a challenge for contemporary organic synthesis.[1] To date, a list of the most successful methods addressing the indoline/oxindole problem would include intra-and intermolecular Mannich, [2] Heck, [3] and Mukaiyama aldol condensations, [4] as well as alkylation reactions, [5][6][7] cycloadditions, [8] pallyl couplings, [9] cyclopropane ring openings, [10] oxidative couplings, and rearrangements. [11,12] In the course of our studies aimed at the use of 2-thioindoles as precursors to substituted oxindoles and indolines, [13][14][15] we became fascinated with the coupling of 2-thio-3-alkylindoles with vinyl diazoacetates in the presence of Rh II salts because the reaction delivered structurally rich quaternary substituted indolines in high yield and the mechanism was mechanistically interesting (Scheme 1).[16] We did not use this reaction in total synthesis endeavors because it was only modestly diastereoselective when monosubstituted vinyl diazoacetates were used as the coupling partners. [17,18] In terms of the mechanism for the transformation to 3 and 4, an abundance of indirect evidence suggested a [3,3] rearrangement of an intermediate sulfonium ylide (i.e. 7 or 8 to give 9 and 10, Scheme 2).[19] Because of the well-established stability of sulfonium ylides, we presumed that Rh II was important in the generation and delivery of the carbenoid to the thioether, but that it was absent during the subsequent sequence leading to CÀC bond formation and 10 (cf. 7, R'' = CC, Scheme 2). [20] Our previous studies resulted in levels of diastereoselectivity that were similar to those seen with 1, therefore we were surprised when the reaction of bis(thioindole) 11 [21] with 2 gave 12 in relatively high diastereoselectivity (Scheme 3). We became intrigued by the generation of 12 and decided to examine the reaction in more detail by exploring the effect of thioindole substitution on diastereoselectivity. As an aside, the importance of the thioether group in the reaction becomes Scheme 1. 2-Thioindole Rh II -vinyl carbenoid couplings.Scheme 2. Working hypothesis for 2-thioindole Rh II -vinyl carbenoid couplings.Scheme 3. Diastereo-and chemoselective bis(indole) vinyl carbenoid couplings.

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“…23 We found that the reaction of 2-hydroxy(2-indo-3-lyl)acenaphthylen-1(2H)-one 4 with indole 2a in the presence of CAN (10 mol%) and anhydrous C 2 H 5 OH (10 mL) proceeded smoothly giving the 2,2-bis(1H-indol-3-yl)acenaphthylen-1(2H)-one 3a. (Table 2) Encouraged by this result, a number of other indoles were applied to this reaction.…”

mentioning

confidence: 94%

Facile Synthesis of 2,2-Bis(1 H-Indol-3-yl)Acenaphthen-1(2H)-One Derivatives Catalysed by Ceric Ammonium Nitrate

Feng

2010

Journal of Chemical Research

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Ceric ammonium nitrate efficiently catalyses the reaction of acenaphthenequinone with indoles afforded symmetrical 2,2-bis(1H-indol-3-yl)acenaphthen-1(2H)-one in excellent yields within 2h under ethanol refluxing, as well as 2-hydroxy-2-indolylacenaphthen-1(2H)-one with indoles afforded the corresponding unsymmetrical 2,2-bis(1H-indol-3-yl)acenaphthen-1(2H)-one. This provides an efficient route to the synthesis of symmetrical and unsymmetrical 2,2-bis(1H-indol-3-yl)acenaphthen-1(2H)-one derivatives.

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Synthesis and resolution of 2,2'-bis-diphenylphosphino [3,3']biindolyl ; a new atropisomeric ligand for transition metal catalysis

Cited by 117 publications

References 37 publications

Atropselective Dibrominations of a 1,1′‐Disubstituted 2,2′‐Biindolyl with Diverging Point‐to‐Axial Asymmetric Inductions. Deriving 2,2′‐Biindolyl‐3,3′‐diphosphane Ligands for Asymmetric Catalysis

Atropselective Dibrominations of a 1,1′‐Disubstituted 2,2′‐Biindolyl with Diverging Point‐to‐Axial Asymmetric Inductions. Deriving 2,2′‐Biindolyl‐3,3′‐diphosphane Ligands for Asymmetric Catalysis

Highly Diastereoselective Sulfonium Ylide Rearrangements to Quaternary Substituted Indolines

Facile Synthesis of 2,2-Bis(1 H-Indol-3-yl)Acenaphthen-1(2H)-One Derivatives Catalysed by Ceric Ammonium Nitrate

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