25329-35-5Relevant academic research and scientific papers
Experimental and theoretical studies of Diels-Alder dimerization of 1,2,3,4,5-pentachlorocyclopentadiene and of Diels-Alder cycloaddition of polychlorinated cyclopentadienes to norbornadiene
Marchand, Alan P.,Ganguly, Bishwajit,Malagón, Carolina I.,Lai, Huiguo,Watson, William H.
, p. 1763 - 1771 (2003)
Diels-Alder cyclodimerization of 1,2,3,4,5-pentachlorocyclopentadiene (1) affords 2a as the exclusive reaction product. Diels-Alder cycloaddition of 1 to norbornadiene also proceeds stereoselectively to produce a single [4+2] cycloadduct, 4c. The structures of 2a and 4c were established unequivocally via application of single crystal X-ray crystallographic techniques. The origins of the observed diastereofacial selectivity in each of these cycloaddition processes have been investigated by application of semiempirical (AM1 Hamiltonian) and ab initio (Hartree-Fock 3-21G*) calculations. The computational results thereby obtained, which are based upon consideration of the kinetically favored transition state for each of the two cycloaddition reactions studied, are consistent with experiment. These semiempirical and ab initio methods also have been used to investigate the mechanisms of the Diels-Alder reactions that have been used to prepare aldrin and isodrin (7 and 8, respectively). The results thereby obtained suggest that isodrin formation via Diels-Alder cycloaddition of cyclopentadiene to 1,2,3,4,7,7-hexachloronorbornadiene proceeds with kinetic control of product stereochemistry.
Facial Selectivity in the Diels-Alder Reactions of 5-Chloro-, 5-Bromo-, and 5-Iodo-l,3-cyclopentadiene and Derivatives
Wellman, Mark A.,Burry, Lori C.,Letourneau, Johnathon E.,Bridson, John N.,Miller, David O.,Jean Burnell
, p. 939 - 946 (2007/10/03)
A variety of dienophiles was used to assess the facial selectivity of Diels-Alder reactions in a series of 1,3-cyclopentadiene derivatives (1-3, 6-10) in which chlorine, bromine, and iodine were planenonsymmetric atoms pitted against hydrogen or methyl at C-5. The results were rationalized in terms of the major factor controlling the facial selectivity being related to steric hindrance between the diene and the dienophile. Selectivity did not correlate with reactivity. Facial selectivity in the reactions with 4-phenyl-l,2,4-triazoline-3,5-dione as the dienophile was also influenced by a second significant factor, postulated to be filled-orbital repulsion with the halogen substituent.
PHOTOCHEMICAL SYNTHESIS OF 5-SUBSTITUTED PENTACHLOROCYCLOPENTADIENES
Zefirov, N. S.,Kirpichenok, M. A.,Shestakova, T. G.
, p. 795 - 810 (2007/10/02)
The photochemical reactions of hexachlorocyclopentadiene with various classes of organic compounds were studied, and a wide range of new 5-substituted pentachlorocyclopentadienes were obtained.The position of the substituent at the C5 atom of the cyclopentadienyl ring was demonstrated by the use of 13C NMR spectroscopy, x-ray crystallographic analysis, and diene synthesis reactions.The recombination mechanism is discussed as a likely mechanism for the processes.The possibility of optimizing the preparative yields was demonstrated for a number of examples.
