Alkali-metal organomagnesiate complexes as catalysts for highly chemoselective crossed-Tishchenko reactions

Abstract

Five new heterobimetallic magnesiates bearing bidentate dianionic pyrrolyl ligands have been synthesized through co-complexation with alkali-metal reagents and di-n-butylmagnesium. Single-crystal X-ray structural analysis of these complexes revealed a variety of intriguing bonding modes. These alkali-metal (Li, Na, and K) organomagnesiates were utilized as catalysts for cross-coupling Tishchenko reactions with two different aldehydes. The sodium alkyl magnesiate complex {ⁿBuMg[2-(Me₃CNCH₂)C₄H₃N]Na(Et₂O)}_∞ (3) was identified as a competent catalyst, as it exhibited higher catalytic activities and chemoselectivity under mild conditions.