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A Microwave-Assisted Direct Heteroarylation of Ketones Using Transition Metal Catalysis
Published on: February 16, 2020
A neutral homoaromatic heavy allene as a platform for selective conversion to a germylene-coordinated
Daichi Uchida1, Hiroko Yamada1, Yoshiyuki Mizuhata1
1Institute for Chemical Research, Kyoto University Gokasho Uji Kyoto 611-0011 Japan mizu@boc.kuicr.kyoto-u.ac.jp.
None:
We report the synthesis of the first neutral homoaromatic heavy allene, stabilized by a methylene-bridged four-membered framework. Single-crystal X-ray diffraction and DFT calculations reveal a cyclic three-center-two-electron (3c-2e) π interaction, a short bridgehead distance, a delocalized HOMO, and a strongly negative NICS(-1) value (-16.9 ppm), collectively establishing pronounced homoaromaticity. Coordination of 4-dimethylaminopyridine (DMAP) induces a clean and selective transformation into a germylene-coordinated digermavinylidene, without substituent migration. This reactivity originates from LUMO localization at the bridgehead Ge atom supported by Wiberg bond indices and NBO analyses. Our findings highlight neutral homoaromaticity as a structural platform for programmable bonding interconversion in heavy main-group π systems.
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