page_title: Anti-periplanar
hierarchical_section_title: Anti-periplanar
caption_attribution_description: English: Representation of co-planar A-B and C-D bonds with a dihedral angle of 180 degrees
context_page_description: Anti-periplanar is a term used in organic chemistry to describe the A–B–C–D bond angle in a molecule. In this conformer, the dihedral angle of the A–B bond and the C–D bond is greater than +150° or less than −150°. Anti-periplanar is often used in textbooks to mean strictly anti-coplanar, with an A-B C-D dihehedral angle of 180°. In a Newman projection, the molecule will be in a staggered arrangement with the anti-periplanar functional groups pointing up and down, 180° away from each other. Figure 5 shows 2-chloro-2,3-dimethylbutane in a sawhorse projection with chlorine and a hydrogen anti-periplanar to each other.
  Syn-periplanar is similar to anti-periplanar. In the syn-periplanar conformer, the A and D are on the same side of the plane of the bond, with the dihedral angle of A–B and C–D between +30° and −30°.
context_section_description: Anti-periplanar is a term used in organic chemistry to describe the A–B–C–D bond angle in a molecule. In this conformer, the dihedral angle of the A–B bond and the C–D bond is greater than +150° or less than −150° (Figures 1 and 2). Anti-periplanar is often used in textbooks to mean strictly anti-coplanar, with an A-B C-D dihehedral angle of 180° (Figure 3). In a Newman projection, the molecule will be in a staggered arrangement with the anti-periplanar functional groups pointing up and down, 180° away from each other (see Figure 4). Figure 5 shows 2-chloro-2,3-dimethylbutane in a sawhorse projection with chlorine and a hydrogen anti-periplanar to each other.
  Syn-periplanar is similar to anti-periplanar. In the syn-periplanar conformer, the A and D are on the same side of the plane of the bond, with the dihedral angle of A–B and C–D between +30° and −30° (see Figure 2).
caption: Figure 3: Representation of a strictly anti-coplanar conformation. A, B, C, and D are in the same plane and the dihedral angle between A–B and C–D is 180°.
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