摘要:
                                The scope of the alkoxyallene cationic cyclopentannelation reaction has been examined.   Non-hydrogen substituents at both C4 and C5   were required for synthetically    useful yields.    Whereas   the cyclization appeared to be subject to steric constraints, it was relatively insensitive to electronic effects.   An efficient synthesis of (d,l)- , desepoxymethylenomycin A methyl ester has been described.