Cyclopentanone synthesis by intramolecular carbon-hydrogen insertion of diazo ketones. A diterpene-to-steroid skeleton conversion

Wenkert, Ernest; Davis, Linda L.; Mylari, Banavara L.; SOLOMON, M. F.; Silva, Roberto R. Da; Shulman, Sol; Warnet, Ronald J.; Ceccherelli, Paolo; Curini, Massimo; Pellicciari, Roberto

doi:10.1021/jo00138a008

Cited by 93 publications

(33 citation statements)

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“…Selective intramolecular C-H insertion provided β-ketoester 18 in excellent yield 33. Treatment of β-ketoester 18 with arylsilyl triflate 17 , available in 5 steps from sesamol,34 in the presence of cesium fluoride22a afforded ketoester (±)- 16 , thereby generating the polycyclic carbon framework of amurensinine in rapid fashion.…”

Section: Resultsmentioning

confidence: 99%

Pd-Catalyzed Enantioselective Aerobic Oxidation of Secondary Alcohols: Applications to the Total Synthesis of Alkaloids

et al. 2008

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Enantioselective syntheses of the alkaloids (−)-aurantioclavine, (+)-amurensinine, (−)-lobeline, and (−)-and (+)-sedamine are described. The syntheses demonstrate the effectiveness of the Pd-catalyzed asymmetric oxidation of secondary alcohols in diverse contexts and the ability of this methodology to set the absolute configuration of multiple stereocenters in a single operation. The utility of an aryne C-C insertion reaction in accessing complex polycyclic frameworks is also described.

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Section: Resultsmentioning

confidence: 99%

Pd-Catalyzed Enantioselective Aerobic Oxidation of Secondary Alcohols: Applications to the Total Synthesis of Alkaloids

et al. 2008

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“…Wenkert et al first applied this reactivity in the context of an intramolecular reaction. [156] In this case,C À Cb ond formation occurs at the allylic CÀHb ond of a-diazo ketone 371,w ith dirhodium acetate as ac atalyst, to give cyclopentanone 372.T abera nd Petty found that unactivated C(sp 3 )ÀHb onds also undergo the reaction, as exemplified by the formation of cyclopentanone 374 from a-diazo-b-keto ester 373 through the transfer of acarbene. [157] Themechanism of the C À Hinsertion step is believed to be concerted, but asynchronous,leaving apartial positive charge at the carbon atom of the CÀHbond.…”

Section: Carbene Transfermentioning

confidence: 99%

Complementary Strategies for Directed C(sp³)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation, Hydrogen Atom Transfer, and Carbene/Nitrene Transfer

2017

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The functionalization of C(sp3)−H bonds streamlines chemical synthesis by allowing the use of simple molecules and providing novel synthetic disconnections. Intensive recent efforts in the development of new reactions based on C−H functionalization have led to its wider adoption across a range of research areas. This Review discusses the strengths and weaknesses of three main approaches: transition‐metal‐catalyzed C−H activation, 1,n‐hydrogen atom transfer, and transition‐metal‐catalyzed carbene/nitrene transfer, for the directed functionalization of unactivated C(sp3)−H bonds. For each strategy, the scope, the reactivity of different C−H bonds, the position of the reacting C−H bonds relative to the directing group, and stereochemical outcomes are illustrated with examples in the literature. The aim of this Review is to provide guidance for the use of C−H functionalization reactions and inspire future research in this area.

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“…In this respect, CH insertions are more characteristic, and their occurrence provides strong evidence for carbenoid reactions. Rh"-Catalyzed diazo decompositions led often to substantial amounts of insertion products when appropriate precursors were used [31]. The intramolecular insertion of diazo ester 13b reportedly proceeded with [Rh,(OAc),] to the cyclic keto ester 14 in 95 YO yield [32].…”

Section: Rel To Styrene (3a)mentioning

confidence: 99%

Carbenoid Reactions in Rhodium(II)‐Catalyzed Decomposition of Iodonium Ylides

Müller

Fernández

1995

Helvetica Chimica Acta

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The intermediacy of metallocarbenes in decomposition reactions of iodonium ylides with [Rh,(OAc),] was established by comparison with reactions of the corresponding diazo compounds. The sensitivity of the Rh"-catalyzed intermolecular cyclopropane formation from substituted styrenes and bis(methoxycarbonyl)(phenyliodono)methanide (la) or dimethyl diazomalonate (lb) is identical. The Hummerr plot (with a ' ) has a slope of -0.47. Iodonium ylides and diazo compounds afford the same products in [Rh,(OAc),]-catalyzed cyclopropane formations, cycloadditions, and intramolecular CH insertions, and exhibit the identical selectivity in intramolecular competitions for cyclopropane formation and insertion. The intramolecular CH insertion of the ylide ZOe, when carried out in the presence of a chiral catalyst ([Rh2{(-)-(S)-ptpa}4]), results in formation of 21a having an ee of 67%, identical to the ee obtained with the diazo compound 20b.Introduction. -The decomposition of diazoketones and diazoesters in the presence of chiral transition-metal catalysts has a remarkable potential for asymmetric catalysis [I]. Cu-Based catalysts [2-51 found successful applications in intermolecular cyclopropane formation with olefins, while chiral Rh"-complexes provided products of intramolecular cyclopropane formation [6], CH insertion [7-91, and intermolecular cyclopropene formation of acetylenes [lo] having enantiomeric excesses in the range of 95% or more. The major drawback of these reactions is the requirement of diazo compounds as precursors which are potentially explosive, toxic, or/and carcinogenic [ 1 11.The transition-metal-catalyzed decomposition of diazo compounds leads to metallocarbenes which are not isolable, but transfer the carbene moiety to a suitable acceptor molecule or to an appropriate reactive site within the metallocarbene [l]. Thus, the use of diazo compounds might be avoided if it were possible to generate the metallocarbenes from other precursors. This investigation deals with the use of iodonium ylides [12-151 as precursors for metallocarbenes in view of their application to asymmetric catalysis.The photochemical and transition-metal-catalyzed decomposition of iodonium ylides such as l a (bis(methoxycarbonyl)(phenyliodono)methanide) [

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Cyclopentanone synthesis by intramolecular carbon-hydrogen insertion of diazo ketones. A diterpene-to-steroid skeleton conversion

Cited by 93 publications

References 1 publication

Pd-Catalyzed Enantioselective Aerobic Oxidation of Secondary Alcohols: Applications to the Total Synthesis of Alkaloids

Pd-Catalyzed Enantioselective Aerobic Oxidation of Secondary Alcohols: Applications to the Total Synthesis of Alkaloids

Complementary Strategies for Directed C(sp³)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation, Hydrogen Atom Transfer, and Carbene/Nitrene Transfer

Carbenoid Reactions in Rhodium(II)‐Catalyzed Decomposition of Iodonium Ylides

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Cyclopentanone synthesis by intramolecular carbon-hydrogen insertion of diazo ketones. A diterpene-to-steroid skeleton conversion

Cited by 93 publications

References 1 publication

Pd-Catalyzed Enantioselective Aerobic Oxidation of Secondary Alcohols: Applications to the Total Synthesis of Alkaloids

Pd-Catalyzed Enantioselective Aerobic Oxidation of Secondary Alcohols: Applications to the Total Synthesis of Alkaloids

Complementary Strategies for Directed C(sp3)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation, Hydrogen Atom Transfer, and Carbene/Nitrene Transfer

Carbenoid Reactions in Rhodium(II)‐Catalyzed Decomposition of Iodonium Ylides

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Complementary Strategies for Directed C(sp³)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation, Hydrogen Atom Transfer, and Carbene/Nitrene Transfer