Rotational selectivity in cyclobutene ring openings. Model studies directed toward a synthesis of verrucarin A

BM Trost, PG McDougal

Index: Trost, Barry M.; McDougal, Patrick G. Journal of Organic Chemistry, 1984 , vol. 49, # 3 p. 458 - 468

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Citation Number: 42

Abstract

The rotational selectivity in the opening of dissymmetric cyclobutenes to the corresponding dienes is described. In the opening of the monoesters of cis-3, 4-cyclobutenedicarboxylic acid, an unusual solvent effect on the ring opening is noted. Switching from Me@ O to 1, 2- dichloroethane leads to a 3: l ratio of the (E, Z)-muconates, favoring the ester on the E double bond. The two isomers can be differentiated by 13C NMR spectroscopy in which ...