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Stereocontrolled Synthesis of Spiro[ n .2]alkenes by Ring Contraction of Fused‐Cyclobutanols
Author(s) -
Takasu Kiyosei,
Nagamoto Yuuki,
Takemoto Yoshiji
Publication year - 2010
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201000930
Subject(s) - cyclopropane , undecane , indane , chemistry , ring strain , contraction (grammar) , ring (chemistry) , stereochemistry , organic chemistry , medicine
An unusual ring‐contraction rearrangement to give spirocyclopropanes from fused cyclobutanols (see scheme) has been developed. It is found that the strain energy of the substrates derived from an additional fused ring and the stereoelectronic effect of the migrating σ bond are important factors. It is noteworthy that the rearrangement proceeds in a stereospecific manner. Moreover, the method provides a spiro(cyclopropane–indane) framework from tricyclo[6.3.0.02,5]undecane, which corresponds to illudane and the protoilludane skeleton.