Electrostatic control of the stereochemistry of nucleophilic additions to substituted 7-norbornanones

Paddon-Row, M. N.; Wu, Yong; Houk, K. N.

doi:10.1021/ja00052a071

Cited by 93 publications

(61 citation statements)

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“…It fails, however, to reproduce relative transition state energies and is thus unreliable in predicting the diastereoselectivities for this reaction (see supporting information). This is surprising since electrostatic effects have been used to explain syn or anti preferences, 109 and the QM/MM approaches have so far been successful in modeling these effects. A careful examination of the ab initio and QM/MM results 44 shows that the Coulomb forces between the QM and MM fragments are much less significant in directing the side of LiH attack than in a previous model 44,109 where LiH is represented by classical point charges interacting with the ketone.…”

Section: Nucleophilic Addition To Carbonyl Compoundsmentioning

confidence: 99%

Hybrid Models for Combined Quantum Mechanical and Molecular Mechanical Approaches

1996

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A hierarchy of three models for combined quantum mechanical (QM) and molecular mechanical (MM) approaches is presented. They simplify the QM description of large molecules by reducing it to the electronically important fragment which interacts with the molecular mechanically treated remainder of the molecule. In the simplest model A, the QM fragments are only mechanically embedded in their MM environment. The more refined models B and C include a quantum mechanical treatment of electrostatic interactions between the fragments and a semiclassical description of polarization. The implementation of models A-C for MNDO type wavefunctions and the MM3 force field is outlined. Selected applications in organic chemistry are discussed, addressing the ability of the proposed models to reproduce substituent effects (MM) on chemical structure and reactivity (QM). These applications include protonations, deprotonations, hydride transfer reactions, nucleophilic additions, and nucleophilic ring cleavage reactions

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Section: Nucleophilic Addition To Carbonyl Compoundsmentioning

confidence: 99%

Hybrid Models for Combined Quantum Mechanical and Molecular Mechanical Approaches

1996

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“…15 Among the many models, transitionstate hyperconjugation [15][16][17] and electrostatic field interaction 18,19 are two popular explanations for face selectivity. Extended studies of reactions of 5-substituted adamantan-2-ones and their derivatives suggest that the reagent prefers to attack the face antiperiplanar to the more electron-rich vicinal bonds.…”

Section: Scheme 5 Synthesis Of Substituted 2-hydroxymethyl Quinuclidmentioning

confidence: 99%

Synthesis of Enantiopure 3-Quinuclidinone Analogues with Three Stereogenic Centers: (1S,2R,4S)- and (1S,2S,4S)-2-(Hydroxymethyl)-1-azabicyclo[2.2.2]octan-5-one and Stereocontrol of Nucleophilic Addition to the Carbonyl Group

Frackenpohl

Hoffmann

2000

J. Org. Chem.

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The pseudoenantiomeric title compounds have been prepared from quincorine (QCI) and quincoridine (QCD), respectively, in enantiopure form following an efficient six-step pathway. Nucleophilic attack at the carbonyl group proceeds preferentially from the supposedly more hindered endo pi-face, giving quinuclidinols with natural configuration at C5 (up to 97%). pi-Face selectivity is highest in the QCD series with bulky O-protecting groups, involving an unprecedented 1,7-stereoinduction.

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“…Both, mono and disubstitutedsilylated 1,3‐butadienes such as‐trimethylsilyl‐1,3‐butadienes 57 (a) or 1,4‐bis(trimethylsilyl)‐1,3‐butadienes 57 (b, c) have been used in the reaction ( Scheme ) . 7‐norbornenones find various applications in organic synthesis and polymer chemistry . The reaction between some tetrasubstituted 1,3‐butadienes can be performed straightforwardly with maleic anhydride under relatively harsh conditions, but the addition of 2 equiv.…”

Section: Cycloaddition Reactions As a Main Tool For Developing Sustaimentioning

confidence: 99%

Aluminum‐Based Catalysts for Cycloaddition Reactions: Moving One Step Ahead in Sustainability

Dogra

Gupta

2019

ChemistrySelect

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A large variety of dienes and alkenes can be derived from plants and used further for the production of fine chemicals or biologically active compounds. Herein, we have identified such dienes/alkenes, as well as their synthetic analogues, and presented a strategy for their conversion by atom-economical cycloaddition reactions. The catalyst used for these conversions is derived from abundantly-available aluminum metal in earth's crust, which has low toxicity, easy availability and low price in comparison to the transition metals. Astonishingly, the applications of aluminum-based catalysts are underdeveloped in comparison to the d-block metal analogues. Therefore, this review summarizes the developments in the field of cycloaddition reactions by using aluminum-based catalysts, a pathway that can be pursued for developing "Sustainable Processes". . Zeolite (81) catalysed cycloaddition of isoprene with dienes 38 (a-d) Scheme 22. Synthesis of TCPD by oligomerization of DCPD and DCPD oligomer isomerisationReviews

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Electrostatic control of the stereochemistry of nucleophilic additions to substituted 7-norbornanones

Cited by 93 publications

References 0 publications

Hybrid Models for Combined Quantum Mechanical and Molecular Mechanical Approaches

Hybrid Models for Combined Quantum Mechanical and Molecular Mechanical Approaches

Synthesis of Enantiopure 3-Quinuclidinone Analogues with Three Stereogenic Centers: (1S,2R,4S)- and (1S,2S,4S)-2-(Hydroxymethyl)-1-azabicyclo[2.2.2]octan-5-one and Stereocontrol of Nucleophilic Addition to the Carbonyl Group

Aluminum‐Based Catalysts for Cycloaddition Reactions: Moving One Step Ahead in Sustainability

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