Names | |
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Preferred IUPAC name
Cyclopentyne | |
Identifiers | |
3D model (
JSmol)
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PubChem
CID
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CompTox Dashboard (
EPA)
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Properties | |
C5H6 | |
Molar mass | 66.103 g·mol−1 |
Except where otherwise noted, data are given for materials in their
standard state (at 25 °C [77 °F], 100 kPa).
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Cyclopentyne is a cycloalkyne containing five carbon atoms in the ring. Due to the ideal bond angle of 180° at each atom of the alkyne but the structural requirement that the bonds form a ring, this chemical is a highly strained structure, and the triple bond is highly reactive. The triple bond easily undergoes both [2+2] and [4+2] cycloaddition reactions. [1] Unlike benzyne, which undergoes a [2+2] addition with loss of stereochemistry at the alkene partner, cyclopentyne reacts with alkenes with retention of geometry of the partner, [2] an example of the relevance of orbital symmetry even for highly reactive structures. [3] The structure can also form a π complex with lithium cations, which affects the cycloaddition reactivity. [1] It can even interact strongly enough with copper species to form a novel type of metallacycle. [4]