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On the Regioselectivity and Stereoselectivity of the Carbene Transfer from Fischer Carbene Complexes to Trisubstituted Electron‐Deficient 1,3‐Dienes
Author(s) -
Buchert Matthias,
Hoffmann Matthias,
Reißig HansUlrich
Publication year - 1995
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19951280613
Subject(s) - cyclopropanation , chemistry , carbene , regioselectivity , stereoselectivity , moiety , olefin fiber , transition metal carbene complex , double bond , medicinal chemistry , stereochemistry , organic chemistry , catalysis
Thermal reactions of Fischer carbene complex 1 with trisubstituted electron‐deficient 1,3‐dienes 7, 8, 23, 25, 32 , and 35 provided highly substituted vinylcyclopropanes in good yields. The carbene transfer proceeds highly regioselectively favouring cyclopropanation of the double bond not bearing the ester function. In addition, the diastereoselectivity is generally fairly high in preference of cyclopropanes with the methoxy group cis ‐positioned with respect to the olefin moiety. The reaction of methylcarbene complex 2 with diene ester 8 displays inversed regioselectivity. These observations are discussed together with solvent effects, and a mechanistic rationale is presented.