Spectroscopic Studies of 1‐Aryl‐2,2‐Dichlorocyclopropanes

Lin, Shaw‐Tao; Yao, Yi‐Fen

doi:10.1002/jccs.199200071

Cited by 6 publications

(1 citation statement)

References 28 publications

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“…The regioselectivity of nitration is controlled by activation of the phenyl ring by a methoxyl (or methyl) group and the cyclopropyl ring as well as by a steric effect which reduces the possibility of the formation of a coplanar state between the two rings for the nucleophilic reaction of the cyclopropyl ring. The donor nature of the dihalogenocyclopropyl ring has been demonstrated by character of examining SCS (substituent chemical shifts) in 13 C NMR analyses . As expected, treating 1-bromo-2-phenylcyclopropane with the nitrosyl salt yields 3-phenylisoxazole as the major product along with benzoic acid from the oxidation reaction.…”

Section: Resultsmentioning

confidence: 78%

Reaction of Halogenated Cyclopropanes and Nitrosyl Cation: Preparation of Isoxazoles

1997

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Section: Resultsmentioning

confidence: 78%

Reaction of Halogenated Cyclopropanes and Nitrosyl Cation: Preparation of Isoxazoles

1997

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Nitration of 2‐Aryl‐1,1‐dihalocyclopropanes Containing Methyl or Phenyl Group

Lin¹,

Lin

Yang

1998

J Chinese Chemical Soc

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Carbon‐13 Nuclear Magnetic Resonance Spectroscopic Analyses of 3‐Aryl‐3‐hydroxyl‐2,2,4,4‐tetramethylcyclobutanones and Related Compounds

Lin

Yeh

2000

J Chinese Chemical Soc

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A series of 2-ary l-2-hydroxy-l, 1,3,3 -tetramethyl-5,8-dioxaspiro[3.4]octanes (1), 3-aryl-3 -hydyoxyl-2,2,4,4-tetyramethylcyclobutanones (2), and l-aryl-2,2,4-trimethy1-1 ,3-pentadiones (3) were studied using l3C NMR analyses. The chemical shifts of C-c are dependent on the substituent groups on the phenyl ring for compounds 1 (p =-0.966, R 2= 0.987) and 2 (p = -1.378, R 2 = 0.998). The chemical shifts ofC-a follow a similar trend (p =-0.926, R 2 = 0.989). In the case of compounds 3, C-c yielded the opposite trend with very poor correlation coefficiency (p = 1.22, R 2 = 0.179). This result reveals the field effect of a polar bond and resonance-induced changes in pi electron-density at C-l on the cyclobutane ring series. 275Because of its small size, rigid geometry, and strain energy, cyclobutanes have been a fascinating subject for theoretical investigation.' Dowd and Sachdev prepared 3-methylenecyclobutanone, observed a band at 215 nm (8 1,550), and suggested that it was a n~n* charge-transfer band which arose as a result of puckering of the cyclobutane ring and consequent overlap of the st-orbitals of the ketone and the double bond.2 Further evidence suggesting 1,3n-interaction was also reported for malononitrile derivatives of 1,3-cyclobutadione and tetramethyl-l,3-cyclobutadione itsele Nuclear magnetic resonance (NMR) spectroscopy is the most sensitive method to determine the electron density around a specific nucleus. The l3Cchemical shift is known to be correlated with the electron density of carbon derived from CNDO/2 calculations and with the Hammett substituent constant (F)4 Several studies of halogenocyclopropanes provided such information 5 In this work, we used NMR techniques to study the possible interaction between C-a and C-c by means of SCS upon the change of substituent on the phenyl ring to this cyclobutane ring. RESULTS AND DISCUSSIONThe chemical shifts of the specific nucleus were strongly dependent on the electron density around, which was influenced by the neighboring group. The l3C chemical shifts were known to be correlated with the Hammett substituent constant (F)6 Therefore, the substituent chemical shift (SCS) of carbon represented the variation of the electron densities with variation of the substituents. By employing this concept it is feasible to study the possible interaction between the aryl group on C-a and C-c of the cyclobutane system. The l3C chemical shifts of the carbonyl of the l-aryl-l,3-pentadiones were also studied for comparison.The carbon of carbonyl had low sensitivity and it was even lower in the cyclobutanone series. To give higher relative signals, we used the short pulse width condition (pulse angle 5°) to cumulate the carbon signals. The l3C chemical shifts of 2-aryl-2-hydroxyl-l, 1,3 ,3-tetramethyl-5,8-dioxaspiro[3.4]octanes (La-Tl), 3-aryl-3-hydroxyl-2,2,4,4-tetramethylcyclobutanones (2a~21), and l-aryl-2,2,4-trimethylo 0

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Spectroscopic Studies of 1‐Aryl‐2,2‐Dichlorocyclopropanes

Cited by 6 publications

References 28 publications

Reaction of Halogenated Cyclopropanes and Nitrosyl Cation: Preparation of Isoxazoles

Reaction of Halogenated Cyclopropanes and Nitrosyl Cation: Preparation of Isoxazoles

Nitration of 2‐Aryl‐1,1‐dihalocyclopropanes Containing Methyl or Phenyl Group

Carbon‐13 Nuclear Magnetic Resonance Spectroscopic Analyses of 3‐Aryl‐3‐hydroxyl‐2,2,4,4‐tetramethylcyclobutanones and Related Compounds

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