Electrocyclic reactions

11 real reactions from the literature: 4π electrocyclization on cyclic conjugated dienes and cyclobutenes; 6π electrocyclization on conjugated trienes. Each scheme shows starting materials, conditions and products, with the yield and reference where the source reports them.

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1. 4π electrocyclization: cyclopentadiene (a cyclic conjugated diene) with hν; THF gives bicyclo(2.1.0)pent-2-ene (the cyclobutene).

   4π electrocyclizationOrg. Synth. Coll. Vol. 6, p. 145

2. 6π electrocyclization: oxepin (a conjugated triene) with 6e dis gives benzene oxide (the cyclohexadiene). 91% yield.

   6π electrocyclizationAngew. Chem. Int. Ed. 1967, 6, 402

3. 4π electrocyclization: (1Z,3E)-cycloocta-1,3-diene (a cyclic conjugated diene) with 80 C; 4e con gives the cyclobutene. 100% yield.

   4π electrocyclizationJ. Am. Chem. Soc. 1965, 87, 3996

4. 6π electrocyclization: a conjugated triene with 60 C; 6e dis gives 5-tert-butyl-6-cyclohexylidenecyclohexa-1,3-diene (the cyclohexadiene). 91% yield.

   6π electrocyclizationJ. Org. Chem. 1992, 57, 796

5. 4π electrocyclization: a cyclobutene with mesitylene (solvent); 4e con gives the cyclic conjugated diene. 78% yield.

   4π electrocyclizationJ. Org. Chem. 1989, 54, 2267

6. 6π electrocyclization: a conjugated triene with 60 C, PhMe gives the cyclohexadiene. 98% yield.

   6π electrocyclizationAngew. Chem. Int. Ed. 2003, 42, 549

7. 4π electrocyclization: a cyclic conjugated diene with 100 C; 4e con gives the electrocyclic product.

   4π electrocyclizationAngew. Chem. Int. Ed. 2017, 56, 4839

8. 6π electrocyclization: a conjugated triene with 150 C; 6e dis gives 5,5-dimethyl-5H-benzocycloheptene (the cyclohexadiene).

   6π electrocyclizationAngew. Chem. Int. Ed. 1978, 17, 208

9. 4π electrocyclization: a cyclic conjugated diene with hv; 4e dis gives the cyclobutene.

   4π electrocyclizationTetrahedron Lett. 1981, 22, 3115

10. 6π electrocyclization: a conjugated triene with 225 C; 6e dis gives 1-ethyl-1,2-dihydronaphthalene (the cyclohexadiene).

    6π electrocyclizationHelv. Chim. Acta 1970, 53, 173

11. 6π electrocyclization: 1,2-bis[(E)-prop-1-enyl]benzene (a conjugated triene) with 225 C; 6e dis gives the cyclohexadiene.

    6π electrocyclizationHelv. Chim. Acta 1970, 53, 173