Product formation and identification in the reaction of 6-endo-hydroxy-5-exo-iodo-3-exo-phenylnorborn-2-endo-ylcarboxylic acid γ-lactone with silver toluene-p-sulphonate

Abstract

The reaction of 6-endo-hydroxy-5-exo-iodonorborn-2-endo-ylcarboxylic acid γ-lactone with silver toluene-p-suiphonate affords 7-syn-hydroxy-3-exo-tosyloxynorborn-6-exo-ylcarboxylic acid γ-lactone as the sole product. A comparable reaction with 6-endo-hydroxy-5-exo-iodo-3-exo-phenylnorborn-2-endo-ylcarboxylic acid γ-lactone affords a mixture of 6-endo-hydroxy-3-exo-phenyl-5-exo-tosyloxynorborn-2-endo-ylcarboxylic acid γ-lactone, 7-syn-hydroxy-5-endo-phenyl-3-exo-tosyloxynorborn-6-exo-ylcarboxylic acid γ-lactone, and 2-exo-hydroxy-4-phenylnorborn-5-en-7-anti-ylcarboxylic acid γ-lactone. Product formation is discussed in terms of possible carbocation intermediates. The latter product is unusual in that the position of the bridgehead C-1 proton in the ¹H n.m.r. spectrum is similar to that of the aromatic protons. Product structures were determined by n.m.r. spectroscopic studies, and by chemical conversions.