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Thermally Induced [2+2] Cycloadditions of (Benzyloxymethylene)cyclopropane with Alkylidenemalononitriles
Author(s) -
Nakamura Itaru,
Nagata Ryoko,
Nemoto Tetsuya,
Terada Masahiro,
Yamamoto Yoshinori,
Späth Thomas,
de Meijere Armin
Publication year - 2007
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200700531
Subject(s) - chemistry , cyclobutane , cyclopropane , cyclobutanes , malononitrile , acetonitrile , yield (engineering) , medicinal chemistry , organic chemistry , catalysis , ring (chemistry) , materials science , metallurgy
The reaction of (benzyloxymethylene)cyclopropane ( 1a ) with alkylidenemalononitriles 2 at ambient pressure afforded the corresponding cyclobutane derivatives 3 in good‐to‐high yields. For example, the reaction of 1a with benzylidenemalononitrile ( 2a ), (2‐naphthylmethylene)malononitrile ( 2e ), and tert ‐butylmethylenemalononitrile ( 2f ) in acetonitrile at 80 °C gave the corresponding cyclobutanes 3a , 3e , and 3f in 96, 96, and 91 % yield, respectively. Control experiments proved that the reaction proceeds via well‐stabilized zwitterionic intermediate 6 . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)