Diene Salts of the Adamantane Series: Synthesis, Structure, and Chemical Transformations

Abstract

Mono‐ and bis‐pyridinium, phosphonium and sulfonium allylic salts, containing adamantane fragment, have been obtained from the substitution reaction in 1,4‐dibromo‐2‐butene. It was found, that the attack of triethylamine undergoes from the sterically less hindered side, leading to deprotonation and subsequent elimination of the molecular fragment with the formation of a new salt of diene structure. Quantum chemical calculations were used to confirm the structure of one of the products by correlation analysis of experimental and calculated NMR data that confirmed the s‐cisoid conformation of the diene. It was found, that obtained dienes may be used as substrates in Diels‐Alder reaction despite their high sterical hinderance.