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These groups are characterized by i) an n-fold proper rotation axis C n; ii) n 2-fold proper rotation axes C 2 normal to C n; iii) a mirror plane σ h normal to C n and containing the C 2 s. The D 1h group is the same as the C 2v group in the pyramidal groups section. The D 8h table reflects the 2007 discovery of errors in older references. [4]
While it is possible for neighbouring groups to influence many reactions in organic chemistry (e.g. the reaction of a diene such as 1,3-cyclohexadiene with maleic anhydride normally gives the endo isomer because of a secondary effect {overlap of the carbonyl group π orbitals with the transition state in the Diels-Alder reaction}) this page is ...
One of the two meso isomers of 1,2,3,4-tetrafluorospiropentane, with S 4 symmetry. Since a meso isomer has a superposable mirror image, a compound with a total of n chiral centers cannot attain the theoretical maximum of 2 n stereoisomers if one of the stereoisomers is meso. [4] A meso isomer need not have a mirror plane.
1,2-Dichloropropane is an intermediate in the production of perchloroethylene and other chlorinated chemicals. [4] It was once used as a soil fumigant , chemical intermediate, as well as an industrial solvent and was found in paint strippers, varnishes, and furniture finish removers but some of these uses have been discontinued.
Mesoionic compounds are a subclass of betaines. [1] Examples are sydnones and sydnone imines (e.g. the stimulant mesocarb ), münchnones , [ 1 ] [ 2 ] and mesoionic carbenes . The formal positive charge is associated with the ring atoms and the formal negative charge is associated either with ring atoms or an exocyclic nitrogen or other atom. [ 3 ]
Enantiotopic groups are identical and indistinguishable except in chiral environments. For instance, the CH 2 hydrogens in ethanol (CH 3 CH 2 OH) are normally enantiotopic, but can be made different (diastereotopic) if combined with a chiral center, for instance by conversion to an ester of a chiral carboxylic acid such as lactic acid, or if coordinated to a chiral metal center, or if ...
The dialkylating group is often a 1,3-, 1,4-, etc. dihalide. [9] In some cases the dialkylating group is a dilithio reagent, such as 1,5-dilithiopentane. [10] For generating spirocycles containing a cyclopropane ring, cyclopropanation with cyclic carbenoids has been demonstrated. [11] Spiro compounds are often prepared by diverse rearrangement ...
Cyclopropane was first produced via a Wurtz coupling, in which 1,3-dibromopropane was cyclised using sodium. [4] The yield of this reaction can be improved by the use of zinc as the dehalogenating agent and sodium iodide as a catalyst. [22] BrCH 2 CH 2 CH 2 Br + 2 Na → (CH 2) 3 + 2 NaBr