Catalytic Enantioselective Nazarov Cyclization: Construction of Vicinal All‐Carbon‐Atom Quaternary Stereocenters

Jolit, Anaïs; Walleser, Patrick M.; Yap, Glenn P. A.; Tius, Marcus A.

doi:10.1002/anie.201403587

Cited by 118 publications

(47 citation statements)

References 48 publications

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“…HMBC correlations from H 3 -19 ( δ H 1.25) to C-1 ( δ C 48.4), C-5, C-9 and C-10 ( δ C 40.6) allowed the A-ring to be assigned as 2-hydroxycyclopentenone (Figure 1). IR bands at 3176 (O–H), 1710 (C=O) and 1670 (C=C) cm −1 supported this assignment [15], as did the UV spectrum (λ max 265 nm). The remaining steroid rings B–D could be accounted for by HMBC (Figure 1) and H2BC (Supplementary Materials, Table S1) correlations.…”

Section: Resultsmentioning

confidence: 86%

Crellasterones A and B: A-Norsterol Derivatives from the New Caledonian Sponge Crella incrustans

2017

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Two new steroids, crellasterones A (1) and B (2), together with the previously reported compound chalinasterol (3) and several nucleosides (4–7), were isolated from the sponge Crella incrustans, collected in New Caledonia. The structures of the new compounds were established by extensive NMR and mass spectroscopic analysis and revealed unprecedented marine natural products with a ring-contracted A-norsterone nucleus and 2-hydroxycyclopentenone chromophore. The absolute configurations were derived from electronic circular dichroism (ECD) measurements in conjunction with high-level density functional theory (DFT) calculations.

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Section: Resultsmentioning

confidence: 86%

Crellasterones A and B: A-Norsterol Derivatives from the New Caledonian Sponge Crella incrustans

2017

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“…The large size of the DPM ether has also proven advantageous in some enantioselective transformations where the bulk provided by the DPM ether provides a steric bias, increasing selectivity in certain substrates. 4 The DPM ether has also been employed in medicinal chemistry to incorporate a large hydrophobic group into biologically active molecules, increasing lipophilicity. 5 …”

Section: Introductionmentioning

confidence: 99%

Formation of DPM ethers using O-diphenylmethyl trichloroacetimidate under thermal conditions

et al. 2016

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Alcohols are effectively converted to their corresponding diphenylmethyl (DPM) ethers by reaction with O-diphenylmethyl trichloroacetimidate in refluxing toluene without the requirement of a catalyst or other additive. A number of acid and base sensitive substrates were protected in excellent yield using this new method without disturbing pre-existing functionality present in these molecules. This reaction is the first example of the formation of an ether from stoichiometric amounts of a trichloroacetimidate and an alcohol without the addition of a Brønsted or Lewis acid catalyst.

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“… For 11aa and 11ac see [a][b]; for 11ba , see [c]; for 11ca , see [d]; for 11ab , see [e]; for 11bb , see [f]; for 11cb , see [g]. …”

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confidence: 99%

The Development of a Stereoselective Method for the Synthesis of Tetrasubstituted Derivatives of α,β‐Unsaturated Carboxylic Acids

Rzymkowski

Piątek

2016

Helvetica Chimica Acta

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Alkenes possessing four different carbon‐linked substituents are the main structural motif of many biologically active compounds. The derivatives of (2E)‐3‐(3‐methoxyphenyl)‐2‐methylpent‐2‐enoic acid ((E)‐2c) are suitable precursors for the synthesis of Tapentadol, a novel centrally acting analgesic. It was found that the Ni‐carbometallation reaction of disubstituted alkyne 8 with CO2 and an Et2Zn allows for efficient and practical preparation of (E)‐2c as a single (E)‐regioisomer in 89% of isolated yield. The influence of the size of the aliphatic substituent of alkyne and the steric hindrance of the organozinc reagent on stereochemical course of the carbometallation reaction was evaluated. Finally, air‐stable Ni(dme)Cl2 was proposed as an alternative to widely used Ni(cod)2 catalyst.

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Catalytic Enantioselective Nazarov Cyclization: Construction of Vicinal All‐Carbon‐Atom Quaternary Stereocenters

Cited by 118 publications

References 48 publications

Crellasterones A and B: A-Norsterol Derivatives from the New Caledonian Sponge Crella incrustans

Crellasterones A and B: A-Norsterol Derivatives from the New Caledonian Sponge Crella incrustans

Formation of DPM ethers using O-diphenylmethyl trichloroacetimidate under thermal conditions

The Development of a Stereoselective Method for the Synthesis of Tetrasubstituted Derivatives of α,β‐Unsaturated Carboxylic Acids

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