[(Me6TREN)MgOCHPh2][B(C6F5)4]: A Model Complex to Explore the Catalytic Activity of Magnesium Alkoxides in Ketone Hydroboration

• Published in: European journal of inorganic chemistry Vol. 2021; no. 45; pp. 4632 - 4638
• Main Authors: Ankur, Kannan, Ramkumar, Chambenahalli, Raju, Banerjee, Sumanta, Yang, Yan, Maron, Laurent, Venugopal, Ajay
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 07.12.2021; Wiley Subscription Services, Inc; Wiley-VCH Verlag
• Subjects: Alkaline earth metals; Alkoxides; Catalytic activity; Chemical Physics; Chemistry; Chemistry, Inorganic & Nuclear; Functional groups; Hydroboration; Inorganic chemistry; Ketone hydroboration; Magnesium; Magnesium alkoxide; Metal hydrides; Nitrogen dioxide; Physical Sciences; Physics; Reaction mechanisms; Reduction catalysis; Science & Technology; ALDEHYDES; Ketone hydroboration; Magnesium alkoxide; HYDRIDE; Alkaline earth metals; SELECTIVE HYDROBORATION; ALUMINUM; REDUCTION; N-HETEROCYCLIC GERMYLENE; CARBONYL; RING-OPENING POLYMERIZATION; CYANOSILYLATION; Reduction catalysis; Reaction mechanisms; EFFICIENT
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.202100651

The sterically hindered monomeric alkoxomagnesium compound [(Me6TREN)MgOCHPh2][B(C6F5)4] (1) has been used to explore the role of magnesium alkoxides in ketone hydroboration. Experiments and DFT calculations are suggestive of a concerted reaction pathway traversing through a six‐membered transition state involving Mg−OCHPh2, B−H, and C=O bonds. Prompted by this hypothesis, we investigated the activity of [Mg(OCHPh2)2] (3), which exhibits turn‐over frequency reaching up to 59,400 h−1 under solvent‐free conditions and stability towards C=C, −OH, −NH2 and −NO2. Due to the non‐existence of a metal hydride intermediate, such catalytic reactions will not get hindered in the presence of additional reactive functional groups. Mechanistic insights on ketone hydroboration using [(Me6TREN)MgOCHPh2][B(C6F5)4] shed light on a concerted activation pathway involving Mg−OCHPh2, B−H and C=O bonds