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Unusual Side Transformation of Spiro[2,4]hepta‐4,6‐dienes into Fulvene Derivatives During Pd‐Catalyzed Cyclopropanation with Diazomethane
Author(s) -
Shulishov Evgeny V.,
Pantyukh Olga A.,
Menchikov Leonid G.,
Tomilov Yury V.
Publication year - 2020
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.202000160
Subject(s) - cyclopropanation , diazomethane , fulvene , chemistry , moiety , medicinal chemistry , methylene , catalysis , ring (chemistry) , methylenecyclopropane , palladium , diazo , diene , stereochemistry , organic chemistry , natural rubber
The catalytic cyclopropanation of spiro[2.4]hepta‐4,6‐diene and 1,1,2,2‐tetradeutero‐, 1‐methyl‐, and 1,1‐dimethylspiro[2.4]hepta‐4,6‐dienes on treatment with excess diazomethane in the presence of palladium catalysts, which gives products of double bond dicyclopropanation, is also accompanied by an unusual transformation of the three‐membered ring of the spiro moiety with elimination of the unsubstituted methylene group in the form of ethylene to give the corresponding 5‐methylidenetricyclo[4.1.0.0 2,4 ]heptanes (bishomofulvenes). The putative mechanism of the reactions is considered.