The formation and some reactions of a spirocyclic chroman derived from a 1-Oxaspiro[2.5]octa-5,7-dien-4-one

Abstract

Reaction between the 5-hydroxymethyl-l-oxaspiro[2.5]octa-5,7-dien-4-one (1) and chlorotrimethylsilane gave the spirocyclic chroman (2) in consistently good yields. The spirocyclic chroman (2) reacted with the sodium salt of p-chlorothiophenol (4) to produce the corresponding (p-chloropheny1) thiomethoxy derivative (3). Evidence is presented for a ring-opened product (5) obtained from the reaction of compound (2) with sodium methoxide. ¹H and ¹³C n.m.r. data are reported for the spirocyclic structures (2) and (3) and compound (5) and suggestions as to their mode of formation are presented.