Peracetic acid—Boron trifluoride etherate

Whereas empirical force-field calculations predict a ring A boat conformation for lanost-8-en-3-one, combined empirical force-field-extended Hiickel molecular orbital calculations favour a ring A chair conformation. Europium-shift n.m.r. results indicate that the molecule adopts the latter conformation. Studies on the peracetic acid-boron trifluoride etherate Baeyer-Villiger oxidation of 4,4-dimethyl-3-keto-triterpenoids to 5-lactones (18) and their subsequent ring contraction to y-lactones have been reported. Dehydrogenation of lanost-8-en-3j8-ol with 2,3-dichloro-5,6-dicyanobenzoquinone afforded, in addition to the corresponding 7,9(1 l)-diene, the aromatic seco-lanostane derivatives (19)... 

Whilst catalysts are not normally required for Baeyer-Villiger oxidation using peracids, boron trifluoride etherate has been used to activate peracetic acid in the preparation of macrocyclic ketones (Figure 3.57).256... 

Baeyer-ViUiger oxidation of maeroeyelic ketones (1, 463-464). Mookherjee el al. report that macrocyclic ketones are readily converted into the corresponding lactones in good yield by treatment with 40% peracetic acid in the presence of boron trifluoride etherate. Thus treatment of cyclododecanone (I) in chloroform with boron trifluoride... 

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