Boron trifluoride benzaldehyde adduct

Reetz and co-workers determined the structure of the benzaldehyde-boron trifluoride adduct by X-ray crystallography in 1986 (Fig. 1-1) [8J, which shows that the Lewis acid is placed 1.59 A from the carbonyl oxygen, along the direction of the oxygen lone pair and anti to the phenyl substituent. 

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