Allenes. Part XXVIII. Synthesis of antibiotic lactols and an allenic ester by Claisen rearrangement of prop-2-ynyl vinyl ethers
Abstract
Naturally occurring 4-hydroxy-2-vinylbut-2-en-4-olide (V), an allenic analogue [4-hydroxy-3,3-dimethyl-2-vinylidenebutan-4-olide (VII)], and the corresponding aldehyde ester [ethyl 2-(1-formyl-1-methylethyl)buta-2,3-dienoate (VIII)] have been synthesised by a Claisen-type sigmatropic rearrangement of 3-carboxyprop-2-ynyl vinyl ethers.