We dedicate this paper to Prof. Masahiro Murakami for his outstanding contribution
to organic chemistry.
Cyclobutenes are highly useful synthetic intermediates as well as important motifs
in functional molecules. Herein, we report a straightforward access toward monosubstituted
cyclobutenes from cyclopropyl N-tosylhydrazone. 1,2-Aryl or -alkyl shift of the Rh(II) carbene intermediate plays
the key role in this transformation.
Key words
Rh(II) catalysis -
N-tosylhydrazone - 1,2-shift - metal carbene - cyclobutene - cyclopropane