The cyclic acetals from 1,4,5,6,7,7-hexachloronorborn-5-en-2-endo-ylalkanols

Abstract

The reaction of 1,4,5,6,7,7-hexachloronorborn-5-en-2-endo-ylmethanol with sodium ethoxide to afford the cyclic acetal 5-endo,6,7,7,8-pentachloro-4-exo-ethoxy-3-oxatricyclo[4.2.1.0^4,8]nonane is found to involve the intermediacy of 1,4,5,7,7-pentachloro-6-ethoxynorborn-5-en-2-endo-ylmethanol and 4-exo, 5-endo, 6,7,7,8-hexachloro-3-oxatricyclo[4.2.1.0^4,8]nonane. 6-endo,7,8,8,9-Pentachloro-5-exo-ethoxy- and methoxy-4-oxatricyclo[5.2.1.0^5,9]decane are formed from the reactions of 1,4,5,6,7,7-hexachloronorborn-5-en-2-endo-ylethanol with sodium ethoxide and methoxide, respectively. N.m.r. studies suggested that in these product cyclic acetals the conformation of the pyran ring tends towards a boat rather than a chair form.