Characterization of Highly Coordinated Allylgermanes: Pivotal Players for Enhanced Nucleophilicity and Stereoselectivity. Issue 12 (18th May 2020)

• Record Type: Journal Article
• Authors: Minami, Yohei; Nishida, Kento; Konishi, Akihito; Yasuda, Makoto
• Is Part Of: Chemistry, an Asian journal. Volume 15:Issue 12(2020)
• Page Start: 1852
• Page End: 1857
• Publication Date: 2020-05-18
• Subjects: organogermanium compounds -- group 14 allylmetals -- stereoselective allylation -- homoallyl alcohols; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/asia.202000392
• Languages: English
• ISSNs: 1861-4728

Abstract

Abstract: Allylgermanes with a 4‐, 5‐, and 6‐coordinated germanium center were characterized by X‐ray crystallography. Cationic 6‐coordinated group 14 allylmetals, which were hitherto assumed to be a transition‐state structure of allylations, were successfully isolated. Forming high coordination states significantly enhanced the reactivity of the allylgermanes. In contrast to the 4‐coordinated allylgermanes with low reactivity, the highly coordinated species readily reacted with several aldehydes. Furthermore, the high coordination states exerted a significant effect on the E / Z selectivity of allylation depending on external additives. The coordination structure had a dramatic influence on the electronic and steric environments around the Ge center, enabling the geometrically controlled allylation of aldehydes. Abstract : Structural determination of a series of allylgermanes bearing a 4‐, 5‐, and 6‐coordinated metal center and evaluation of their nucleophilicity has been accomplished. The highly coordinated state enhanced the reactivity of the allyl moiety. The E, Z ‐selectivity toward allylation of aldehydes dramatically changed depending on their coordination structure.