Asymmetric synthesis of alpha substituted benzyl alcohols via the stereoselective addition of nucleophiles to homochiral tricarbonyl(η<sup>6</sup>-o-trialkylsilylbenzaldehyde)chromium(<scp>0</scp>) complexes

Davies, Stephen G.; Goodfellow, C. L.

doi:10.1039/p19900000393

Cited by 63 publications

(28 citation statements)

References 21 publications

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“…34 (-)-1-(S)-(2-Methoxy-phenyl)-ethyl)-amine [(-)-(S)-7b] 35 was synthesized using a method previously described for the preparation of chiral non-racemic benzylic amines via alkylation of chiral imines. 36 (h 6 -Naphthalene) Cr(CO) 3 2, 20,37 and (h 6 -benzaldehyde) Cr(CO) 3 10b, 38 4 were prepared as previously described. All other chemicals were purchased from Aldrich or Fluka and were purified following standard literature procedures.…”

Section: Methodsmentioning

confidence: 99%

Diastereoselective Transformation of Arenes into Highly Enantiomerically Enriched Substituted Cyclohexadienes

Bérnardinelli¹,

Gillet²,

Kündig³

et al. 2001

Synthesis

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Sequential addition of a C-nucleophile and a C-electrophile to enantiomerically pure arene tricarbonyl chromium complexes 3a,b, 6, and 8b, containing aryl bound chiral oxazoline, SAMP-hydrazone and chiral imine auxiliaries affording substituted cyclohexadienes. C-Nucleophiles included alkyl-, vinyl-, and phenyl-lithium reagents. C-Electrophiles included methyl iodide, allyl bromide, benzyl bromide, and propargyl bromides. The 1,3-cylohexadienes were obtained with a 1,5,6-substitution pattern. The results are consistent with a diastereoselective exo-nucleophilic addition to an ortho position of the complexed arene, followed by addition of the electrophile to the metal center. With allyl, ben-zyl, and propargyl groups, direct reductive elimination then yielded trans-5,6-substituted products. With methyl iodide, reductive elimination was preceded by CO insertion and acetyl cyclohexadienes were formed exclusively whose in situ deprotonation/alkylation gave products in which three C-substituents had been added across an arene double bond with complete regio-and stereocontrol. The two path-ways reflect migratory aptitude to carbonylation. An Xray structure determination of the phenyl oxazoline complex 3a allowed a rationalization of observed diastereoselectivity. Asymmetric induction was very high with the oxazoline and the SAMPhydrazone complexes (>90% de) whereas the chiral benzaldehyde imine complex 8b afforded the substituted diene aldehydes in moderate enantiomeric purity (34-58% ee). Changing the reaction medium from THF to toluene in reactions with 8b resulted in products of the opposite chirality.

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Section: Methodsmentioning

confidence: 99%

Diastereoselective Transformation of Arenes into Highly Enantiomerically Enriched Substituted Cyclohexadienes

Bérnardinelli¹,

Gillet²,

Kündig³

et al. 2001

Synthesis

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“…Tricarbonylchromium(0) Complex 2: ( R , R )‐2,2‐Bipyrrolidine ( 1 ; 1.45 g, 10.4 mmol) was added to a solution of (η 6 ‐benzaldehyde)tricarbonylchromium(0)6c (1.67 g, 6.9 mmol) in 20 mL of dry diethyl ether. The reaction mixture was stirred at room temperature in the presence of molecular sieves (4 Å) overnight.…”

Section: Methodsmentioning

confidence: 99%

“…13 C NMR (50 MHz, CDCl 3 ): δ = 0.6, 92.4, 93.2, 93.7, 97.4, 100.1, 101.2, 190.8, 230.9 ppm. [α] D 21 = +140 ( c = 0.0015, CHCl 3 ), [α] D 21 = –147 ( c = 0.0014, EtOH) for ee 91 % [ref 6c. [α] D 21 = –154 ( c = 0.001, CHCl 3 )].…”

Section: Methodsmentioning

confidence: 99%

Diastereoselective Alkylation of (Arene)tricarbonylchromium and Ferrocene Complexes Using a Chiral, C₂‐Symmetrical 1,2‐Diamine as Auxiliary

et al. 2005

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The aminal of (benzaldehyde)tricarbonylchromium and en‐antiopure bipyrrolidine undergoes diastereoselective ortho‐metallation with butyllithium. Quenching with various electrophiles, followed by hydrolysis of the aminal, affords ortho‐substituted (benzaldehyde)tricarbonylchromium compounds with high ee (91–99 %). When quenched with Ph2PCl, a new chiral P,N‐bidentate ligand is obtained, which shows efficiency in Pd‐ and Cu‐catalysed reactions. The aminal of ferrocenecarbaldehyde could also be formed, but the ortho‐deprotonation occurs with only moderate diastereoselectivity (70 %). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

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“…First, construction of the chromium tricarbonyl aldehyde complex, which serves as the linchpin, requires five steps and is not highly efficient 26. The second comprises low atom efficiency, in conjunction with use of chromium, an environmental hazard.…”

Section: Multi-component Reactions Involving Type II Anion Relay Chemmentioning

confidence: 99%

Evolution of multi-component anion relay chemistry (ARC): construction of architecturally complex natural and unnatural products

2008

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Efficient construction of architecturally complex natural and unnatural products is the hallmark of organic chemistry. Anion Relay Chemistry (ARC) -a multi-component coupling protocol -has the potential to provide the chemist with a powerful synthetic tactic, enabling efficient, rapid elaboration of structurally complex scaffolds in a single operation with precise stereochemical control. The ARC tactic can be subdivided into two main classes, comprising the relay of negative charge either through bonds or through space, the latter with aid of a transfer agent. This review will present the current state of through-space anion relay, in conjunction with examples of natural and unnatural product syntheses that illustrate the utility of this synthetic method

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Asymmetric synthesis of alpha substituted benzyl alcohols via the stereoselective addition of nucleophiles to homochiral tricarbonyl(η⁶-o-trialkylsilylbenzaldehyde)chromium(0) complexes

Cited by 63 publications

References 21 publications

Diastereoselective Transformation of Arenes into Highly Enantiomerically Enriched Substituted Cyclohexadienes

Diastereoselective Transformation of Arenes into Highly Enantiomerically Enriched Substituted Cyclohexadienes

Diastereoselective Alkylation of (Arene)tricarbonylchromium and Ferrocene Complexes Using a Chiral, C₂‐Symmetrical 1,2‐Diamine as Auxiliary

Evolution of multi-component anion relay chemistry (ARC): construction of architecturally complex natural and unnatural products

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Asymmetric synthesis of alpha substituted benzyl alcohols via the stereoselective addition of nucleophiles to homochiral tricarbonyl(η6-o-trialkylsilylbenzaldehyde)chromium(0) complexes

Cited by 63 publications

References 21 publications

Diastereoselective Transformation of Arenes into Highly Enantiomerically Enriched Substituted Cyclohexadienes

Diastereoselective Transformation of Arenes into Highly Enantiomerically Enriched Substituted Cyclohexadienes

Diastereoselective Alkylation of (Arene)tricarbonylchromium and Ferrocene Complexes Using a Chiral, C2‐Symmetrical 1,2‐Diamine as Auxiliary

Evolution of multi-component anion relay chemistry (ARC): construction of architecturally complex natural and unnatural products

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Product

Resources

About

Asymmetric synthesis of alpha substituted benzyl alcohols via the stereoselective addition of nucleophiles to homochiral tricarbonyl(η⁶-o-trialkylsilylbenzaldehyde)chromium(0) complexes

Diastereoselective Alkylation of (Arene)tricarbonylchromium and Ferrocene Complexes Using a Chiral, C₂‐Symmetrical 1,2‐Diamine as Auxiliary