Steric attraction

Hoffmann, Roald; Levin, Charles; Moss, Robert A.

doi:10.1021/ja00783a077

Cited by 52 publications

(13 citation statements)

References 5 publications

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“…From 146 mg of trans-2,3-dimethylcyclobutanone14 was obtained approximately 100 µ of liquid that was two overlapping peaks on a 10 ft X V4 in. DBTCP column (100 °C): IR (CC14) 3.28-3.55, 5.90 µ; NMR (CC14, 22 MHz) 1.00-1.18 (8 lines, 6 ), 1.42-1.54 (m, 3 H), 1.77 (m, 1 ), 1.97 (m, 1 H), 2.37 (broad doublet, 7 = 26 Hz, 1 H), 2.66 (m, 1 H), and 5.00 (m, 1 H); m/e 110.1102 (caled for C8Hm, 110.1096).…”

Section: Methodsmentioning

confidence: 99%

Dominant double rotation in the thermally induced 1,2,4-trimethylspiropentane geometric isomerization

Gajewski¹,

Weber²,

Chang³

1979

J. Am. Chem. Soc.

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Section: Methodsmentioning

confidence: 99%

Dominant double rotation in the thermally induced 1,2,4-trimethylspiropentane geometric isomerization

Gajewski¹,

Weber²,

Chang³

1979

J. Am. Chem. Soc.

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“…Steric repulsion (D and D-R3 in 9-11 are normally large and push R' to the antiperiplanar position) [l] [4-91 [15], steric attraction (between R' and R2) [28], the pyramidalized donor centre might cause the preference of the A=C . .…”

Section: ) In a Gauche (Synclinal) Arrangement Of The Donor (C = D)-bmentioning

confidence: 99%

Synthesis of Open‐Chain 2,3‐Disubstituted 4‐nitroketones by Diastereoselective Michael‐addition of (E)‐Enamines to (E)‐Nitroolefins. A topological rule for C, C‐bond forming processes between prochiral centres. Preliminary communication

Seebàch¹,

Golinski

1981

Helvetica Chimica Acta

391

119

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The Michael‐additions of aliphatic, alicyclic, and arylsubstituted nitroolefins and enamines lead to γ‐nitroketones 3 in good chemical and excellent (> 90%) diastereomeric yields (see Table 1). The known threo‐configuration of one type of adducts 3 (entries 8, 10, and 11 of Table 1) can be arrived at by assuming the approach 8 of the Michael‐acceptor and ‐donor; the reaction follows a topological rule, which is formulated and which is applicable to such diverse reactions as the diene synthesis, cyclopropanations, carbonyl olefinations and methylenations, aldol‐ and nitroaldol‐type additions, as well as additions of lithium, boron, and chromium derivatives to aldehydes (see 9, 10, 11, and Table 2).

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“…Ce fait montre que la distribution des isomeres ne depend pas prioritairement de l'interaction sterique attractive Me ... Me dans l'etat de transition, tel que le decrivent Hofmann et al (18). Si tel etait le cas, le trans ethoxy propene devrait donner un accroissement de la quantite de l'isomere cis, au detriment du trans.…”

Section: Discussionunclassified

Méthylhalogénocyclopropanation des éthoxy-alcènes diversement alkylés. Identification stéréochimique des adduits et étude de la stéréosélectivité

Barlet¹,

Goaller²,

Gey³

1982

Can. J. Chem.

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Ethoxy-alkenes act as excellent carbene acceptors in the methylmonohalogenocyclopropanation reaction mediated by 1,1-dichloroethane and iodide-ion free methyl iodide. As well as chlorinated adducts, a large proportion of brominated products are obtained by means of halogen exchange at the carbene complex – salt intermediate stage. Adduct stereochemistry is determined by 1H and 13C nmr spectroscopy. The syn-stereoselectivity of the reaction is discussed in electronic and steric terms. [Journal Translation]

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Steric attraction

Cited by 52 publications

References 5 publications

Dominant double rotation in the thermally induced 1,2,4-trimethylspiropentane geometric isomerization

Dominant double rotation in the thermally induced 1,2,4-trimethylspiropentane geometric isomerization

Synthesis of Open‐Chain 2,3‐Disubstituted 4‐nitroketones by Diastereoselective Michael‐addition of (E)‐Enamines to (E)‐Nitroolefins. A topological rule for C, C‐bond forming processes between prochiral centres. Preliminary communication

Méthylhalogénocyclopropanation des éthoxy-alcènes diversement alkylés. Identification stéréochimique des adduits et étude de la stéréosélectivité

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