Highly regioselective reaction of zirconocene-alkene complexes with aldehydes or ketones

Suzuki, Noriyuki; Rousset, Christophe; Aoyagi, Koichiro; Kotora, Martin; Takahashi, Tamotsu; Hasegawa, Maki; Nitto, Yu; Saburi, Masahiko

doi:10.1016/0022-328x(94)80112-6

Cited by 28 publications

(4 citation statements)

References 28 publications

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“…The addition of styrene derivatives to unactivated ketones is limited by the requirement for stoichiometric transition metal promoters and poor regioselectivity. 30 On the other hand, regioselective coupling of ketyl radicals with styrenes necessitates the use of UV radiation, 31 SmI 2 , 32 or dissolving metals 33 to enable single electron reduction of aliphatic carbonyl compounds. To investigate whether reductive activation of π bonds to radical anions could overcome these limitations, we conducted reduction of diphenylethylene 1 in acetone using a sterically bulky tetramethylpiperidine derivative 47 as a reductive quencher (Figure 4).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Formation of a nucleophilic radical anion from styrene derivatives paves the way for the development of hydrofunctionalization reaction of alkenes with weakly electrophilic coupling partners. The addition of styrene derivatives to unactivated ketones is limited by the requirement for stoichiometric transition metal promoters and poor regioselectivity . On the other hand, regioselective coupling of ketyl radicals with styrenes necessitates the use of UV radiation, SmI 2 , or dissolving metals to enable single electron reduction of aliphatic carbonyl compounds.…”

Section: Results and Discussionmentioning

confidence: 99%

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Reductive Activation and Hydrofunctionalization of Olefins by Multiphoton Tandem Photoredox Catalysis

et al. 2021

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The conversion of olefin feedstocks to architecturally complex alkanes represents an important strategy in the expedient generation of valuable molecules for the chemical and life sciences. Synthetic approaches are reliant on the electrophilic activation of unactivated olefins, necessitating functionalization with nucleophiles. However, the reductive functionalization of unactivated and less activated olefins with electrophiles remains an ongoing challenge in synthetic chemistry. Here, we report the nucleophilic activation of inert styrenes through a photoinduced direct single electron reduction to the corresponding nucleophilic radical anion. Central to this approach is the multiphoton tandem photoredox cycle of the iridium photocatalyst [Ir(ppy) 2 (dtbbpy)]PF 6 , which triggers in situ formation of a high-energy photoreductant that selectively reduces styrene olefinic π bonds to radical anions without stoichiometric reductants or dissolving metals. This mild strategy enables the chemoselective reduction and hydrofunctionalization of styrenes to furnish valuable alkane and tertiary alcohol derivatives. Mechanistic studies support the formation of a styrene olefinic radical anion intermediate and a Birch-type reduction involving two sequential single electron transfers. Overall, this complementary mode of olefin activation achieves the hydrofunctionalization of less activated alkenes with electrophiles, adding value to abundant olefins as valuable building blocks in modern synthetic protocols.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

Reductive Activation and Hydrofunctionalization of Olefins by Multiphoton Tandem Photoredox Catalysis

et al. 2021

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“…The complexes are transformed into zirconacycles via oxidative coupling with another carbon−carbon multiple bond . Additionally, coupling reaction with aldehydes or ketones affords the corresponding saturated alcohols via the oxazirconacyclopentane intermediate . However, reaction of Cp 2 Zr(alkene) with acid halide has not been explored.…”

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confidence: 99%

Conversion of Acid Chloride into Homoallylic Alcohol via Allylic C−H Bond Activation of Alkene with a Zirconocene Complex

et al. 2001

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“…Additionally, coupling reaction with aldehyde or ketone afforded the corresponding saturated alcohol via an oxazirconacyclopentane intermediate (Scheme ) . It is noteworthy that 6a was obtained exclusively and that the regioisomer 6b was not detected.…”

Section: Introductionmentioning

confidence: 99%

Transformation of Zirconocene−Olefin Complexes into Zirconocene Allyl Hydride and Their Use as Dual Nucleophilic Reagents: Reactions with Acid Chloride and 1,4-Diketone

et al. 2004

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Zirconocene-olefin complexes Cp(2)Zr(H(2)C=CHR), prepared in benzene-THF at 0 degrees C, react with acid chlorides to provide homoallylic alcohols. The key is an equilibrium between the zirconocene-olefin complexes and the corresponding zirconocene allyl hydride complexes via allylic C-H bond cleavage of the coordinating alkenes. Furthermore, the zirconocene-olefin complexes are also available for the reaction with 1,4-diketone to afford anti-1,4-diols with excellent diastereoselectivity. Thus, Cp(2)Zr(H(2)C=CHR) serves as a donor of both hydride and an allylic group. These reactions also proceed efficiently by using zirconocene-olefin complexes, derived from Cp(2)ZrCl(2), Mg metal, and 1-alkenes.

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Highly regioselective reaction of zirconocene-alkene complexes with aldehydes or ketones

Cited by 28 publications

References 28 publications

Reductive Activation and Hydrofunctionalization of Olefins by Multiphoton Tandem Photoredox Catalysis

Reductive Activation and Hydrofunctionalization of Olefins by Multiphoton Tandem Photoredox Catalysis

Conversion of Acid Chloride into Homoallylic Alcohol via Allylic C−H Bond Activation of Alkene with a Zirconocene Complex

Transformation of Zirconocene−Olefin Complexes into Zirconocene Allyl Hydride and Their Use as Dual Nucleophilic Reagents: Reactions with Acid Chloride and 1,4-Diketone

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