Synthesis of Adamantane Derivatives. LVIII. Reaction of 1-Adamantyl Chloride with Some Heterocyclic Unsaturated Silanes

Abstract

Various silylated heterocycles having amide functionality were treated with 1-adamantyl chloride (1) in the presence of a Lewis acid to give the corresponding N-adamantylated heterocycles. If α-position to the reacting lactim nitrogen was substituted, the reaction no longer occurred, or the adamantylation occurred at the position other than the expected nitrogen. These facts are attributed to a steric blocking effect of the α-substituent. While the same treatment of the thioamide 46 gave the S-adamantylated product, 48 and 51 afforded in contrast the N- and S-adamantylated products, respectively ; this result can be explained in terms of steric effect. Analogously, silylated 2-pyrazolines and triazoles were adamantylated at nitrogen. The reactions of 2-trimethylsilylthiophene, furan and -pyridine with 1 failed to give site-selective monoadamantylation.