Highly stereoselective cycloadditions of Danishefsky's diene to (−)-8-phenylmenthyl and (+)-8-phenylneomenthyl glyoxylate N-phenylethylimines

Garcı́a-Mera, Xerardo; Alves, M. I. Caetano; Goth, Albertino; Vale, M. Luísa C. do; Rodríguez‐Borges, José E.

doi:10.1016/j.tet.2013.02.027

Cited by 6 publications

(3 citation statements)

References 78 publications

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“…12), effectively raising the energetic barrier posed by the transition states above the energy of the reactants, and giving positive effective activation enthalpies, which are expected from the experimental data. 6,17,42,43,49 This effect becomes more evident with increasing temperature, and is particularly dramatic for the case of DH Exo TS , for which energetic barriers as high as 169.7 kJ mol À1 are observed for the reaction between CP and I16-Im in CH 2 Cl 2 at 298.15 K, thus effectively blocking this reaction pathway. On the other hand, the concurrent endo-3R pathway (for the same reaction) presents an activation enthalpy of only 18.5 kJ mol À1 that decreases with increasing temperature, as demonstrated in the DFT calculations and determined by inspecting Table 2.…”

Section: Solvent Effectsmentioning

confidence: 99%

Simple descriptors for assessing the outcome of aza-Diels–Alder reactions

Teixeira

Cordeiro

2015

RSC Adv.

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The iminium aza-Diels-Alder (iADA) reaction of cyclopentadiene with 16 protonated alkyl alkylimineglyoxilates was studied using density functional theory (DFT) in order to elucidate how different substitution patterns in the dienophile may affect the reaction's outcome. Additionally, the application of the polarisable continuum model (PCM) together with the evaluation of the thermodynamic properties at different temperatures further allowed the surveying of the importance of such factors. These effects were combined into linear models which use the temperature, Taft's constants and characteristics of the solvent as descriptors for modelling and predicting the activation enthalpy and enthalpic balance of the iADA reactions under study. This model performs in a satisfactory manner, providing a cross-validation of the DFT framework traditionally used for predicting the outcome of these reactions and also uncovering novel insights into how the substitution patterns in the dienophile, the solvent and the temperature interact in order to give the characteristic regio-and stereoselectivity of the iADA reaction. Moreover, the results show that Taft's polar and steric substituent constants are important descriptors for assessing the outcome of iADA reactions.

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Section: Solvent Effectsmentioning

confidence: 99%

Simple descriptors for assessing the outcome of aza-Diels–Alder reactions

Teixeira

Cordeiro

2015

RSC Adv.

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“…The proposed reaction mechanism involves the generation of silane–hydrazone complex 598 followed by addition of diene to give allyl cation intermediate 599 , which could be collapse to give [3 + 2] cycloadducts (route a) or [4 + 2] cycloadducts (route b) (Scheme ). Also, three-component aza-Diels–Alder reactions of in situ generated α-imino esters with variety of dienes were reported in the literature. − …”

Section: [4 + 2] Cycloadditionsmentioning

confidence: 97%

α-Imino Esters in Organic Synthesis: Recent Advances

2017

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α-Imino esters are useful precursors for the synthesis of a variety of types of natural and unnatural α-amino acid derivatives, with a wide range of biological activities. Due to the adjacent ester group, α-imino esters are more reactive relative to other types of imines and undergo different kinds of reactions, including organometallics addition, metal catalyzed vinylation and alkynylation, aza-Henry, aza-Morita-Baylis-Hillman, imino-ene, Mannich-type, and cycloaddition reactions, as well as hydrogenation and reduction. This review discusses the mechanism, scope, and applications of the reactions of α-imino esters and related compounds in organic synthesis, covering the literature from the last 12 years.

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“…While the approach of the diene is chiefly from one of the faces, it is in fact steric hindrance which supports the generation of minor conformational intermediates ( 125 b′ and 126 a′ ). In these intermediates the methyl group break apart the attack of the diene from that same face and thus a tiny reduction of the de (87 : 13 and 88 : 12, respectively) is detected; (iii) for all intermediates the 8‐phenyl function provides higher bulkiness on one of the faces of the dienophile, thus PM blocks the Re ‐face and on the hand PNM blocks the Si ‐face …”

Section: Double Asymmetric Induction In the Reaction Of Dainshefsky Dmentioning

confidence: 99%

Applications of Dainshefsky's Dienes in the Asymmetric synthesis of Aza‐Diels‐Alder Reaction

Koshvandi

Heravi

2018

The Chemical Record

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Asymmetric hetero-Diels-Alder (AHDA) reactions provide a multitude of opportunities for the highly efficient, regio- and stereoselective construction of various heterocycles in enantiomerically pure form. The asymmetric aza-Diels-Alder (A-aza-DA) reaction using diversely hetero-dienophiles and hetero-dienes have been increasingly developed as a valuable method for the synthesis of functionalized nitrogen ring systems. The purpose of this review is to give a detailed discussion of the A-aza-DA reaction particularly, the stereoselective reactions of imines as dienophiles with Dainshefsky dienes to obtain optically pure aza-Diels-Alder products. The development of stereoselective variants of the reaction make use of imines as the dienophile and Dainshefsky dienes is at the forefront of these studies. This review updates the A-aza-DA reactions covering the literature from 1972 till date.

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Highly stereoselective cycloadditions of Danishefsky's diene to (−)-8-phenylmenthyl and (+)-8-phenylneomenthyl glyoxylate N-phenylethylimines

Cited by 6 publications

References 78 publications

Simple descriptors for assessing the outcome of aza-Diels–Alder reactions

Simple descriptors for assessing the outcome of aza-Diels–Alder reactions

α-Imino Esters in Organic Synthesis: Recent Advances

Applications of Dainshefsky's Dienes in the Asymmetric synthesis of Aza‐Diels‐Alder Reaction

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