Reactions of oxalyl chloride with 1,2-cycloalkanediols in the presence of triethylamine.
The relationship between the product patterns and the configurations of 1,2-cycloheptane- and 1,2-cyclooctanediols 9 in the cyclocondensations with oxalyl chloride in the presence of triethylamine at 0 degrees C has been shown analogous to that obtained for 1,2-disubstituted acyclic ethylene glycols 1: cis-1,2-cyclooctanediol (9f) produced the cyclic oxalate 14f as the major product, while trans-1,2-cycloheptanediol (9e) and trans-1,2-cyclooctanediol (9g) formed the cyclic carbonates 12e, g as the major products. On the other hand, the cyclic oxalates 14a-d were formed as the major products from 1,2-cyclopentane- and 1,2-cyclohexanediols regardless of the configuration. These results can be accounted for by assuming the boat-like transition states for cyclizations of the half esters of comparatively rigid five- and six-membered diols 9a--d. The cyclic oxalates 14a, c may be directly formed through the resulting tetrahedral intermediates from cis-diols (9a,c), and the cyclic carbonates 12a,c as the minor products after ring inversion of the tetrahedral intermediates. The tetrahedral intermediates from the trans-isomers 9b, d cannot undergo ring inversion, producing no traces of the cyclic carbonates 12b, d.
Itaya
Taisuke
T
Faculty of Pharmaceutical Sciences, Kanazawa University, Japan. itaya@dbs.p.kanazawa-u.ac.jp
Iida
Takehiko
T
Natsutani
Itaru
I
Ohba
Masashi
M
D000473:Alkanes / Q000737:chemistry*; D002712:Chlorides / Q000737:chemistry*; D005021:Ethylamines / Q000737:chemistry*; D010070:Oxalates / Q000737:chemistry*; D013237:Stereoisomerism
D000473:Alkanes; D002712:Chlorides; D005021:Ethylamines; D010070:Oxalates; C092266:oxalyl chloride; C016162:triethylamine