Seven membered ring chelates derived from γ-hydroxyamides and triphenyltin or diphenylboron

N-Benzyl-4-hydroxy-butyramide (1), 4-hydroxy-N-[(R)-1-phenyl-ethyl]-butyramide (2), and (R)-4-hydroxy-2-methyl-N-[(R)-1-phenyl-ethyl]-butyramide (3a) were used to prepare new diphenylboron and triphenyltinoxy compounds: diphenylborinic acid 3-benzylcarbamoyl-propyl ester (4), diphenylborinic acid 3-[(R)-1-phenyl-ethylcarbamoyl]-propyl ester (5) and diphenylborinic acid (R)-3-[(R)-1-phenyl-ethylcarbamoyl]-butyl ester (6), N-benzyl-4-triphenyltinoxy-butyramide (7), 4-triphenyltinoxy-N-[(R)-1-phenyl-ethyl]-butyramide (8), and (R)-4-triphenyltinoxy-2-methyl-N-[(R)-1-phenyl-ethyl]-butyramide (9). The X-ray diffraction analysis of a crystalline structure of the new γ-hydroxyamide 3a is reported, as well as that of the first example of a crystalline structure where a diphenylborinic ester forms a seven membered chelate, by a carbonyl coordination to boron (4). Structural studies of tin and boron esters were performed by NMR. The CO internal coordination to tin atoms, affording seven membered rings, was observed by 119Sn NMR experiments at low temperature.

Graphical abstractSeven membered ring chelates derived from γ-hydroxyamides and triphenyltin or diphenylboron New diphenylboron and triphenyltin compounds derived from γ-hydroxy-amides were prepared. The crystalline structure of (R)-4-hydroxy-2-methyl-N-[(R)-1-phenyl-ethyl]-butyramide is reported, as well as that of the first example of a X-ray diffraction analysis of a crystalline structure where a diphenylborinic ester forms a seven membered chelate diphenylborinic acid 3-benzylcarbamoyl-propyl ester. Structural studies of tin and boron esters were performed by NMR. The CO internal coordination to tin atoms, affording seven membered rings, was observed by 119Sn NMR experiments at low temperature.Figure optionsDownload full-size imageDownload as PowerPoint slide