Synthesis and properties of stable alumoles

GRAPHICAL ABSTRACT

ABSTRACT

Stable alumole and gallole derivatives have been synthesized, and their reactivity was investigated. Mes^*-substituted alumole and gallole have tri-coordinated heavier group 13 element moieties even in the presence of Lewis bases, because of the steric hindrance of the bulky Mes^* group. Treatment of the Mes^*-substituted heavier group 13 heteroles with Li metal afforded the Li salts of the corresponding heterole dianions. Furthermore, 1-bromo- and 1-chloro-alumole derivatives were synthesized by applying the same synthetic method as used for the synthesis of the Mes^*-substituted alumole. In the solid state, the 1-haloalumoles exhibit dimeric structures due to the halogen–aluminum coordination interactions. Utilization of the 1-bromoalumole for the synthesis of new cyclic organoaluminum compounds through the reactions with nucleophiles and alkynes are also described.

KEYWORDS:

• Alumole
• gallole
• alumepin
• 1-haloalumole

Funding

This work was partially supported by the JSPS KAKENHI (Nos. 24109013, 24550048, 2662028, and 15H05477), the MEXT Project of Integrated Research on Chemical Synthesis from the Ministry of Education, Culture, Sports, Science, and Technology (Japan), the “Molecular Systems Research” project of the RIKEN Advanced Science Institute, and the Collaborative Research Program of the Institute for Chemical Research, Kyoto University. T.A. is thankful for the Ube Industries Award in Synthetic Organic Chemistry (Japan). X-Ray crystallographic analysis of compounds 6 and 7 were carried out at the BL26B2 (Proposal No. 2014A1361) and BL38B1 (Proposal No. 2013B1083) of SPring-8, JASRI.