Cyclobutanones Baeyer-Villiger rearrangement

Cyclobutanones are the only ketones that undergo Baeyer-Villiger rearrangements not only with peracids but even with alkaline H202 or alkaline ferf-BuOOH (Figure 11.35). In this case, the driving forces of two crucial reaction steps are higher than... 

Lactones (15) can be made by Baeyer-Villiger rearrangement (Chapter 27) of cyclobutanones. The more highly substituted group migrates with retention of configuration. 

Lactone (16) is an important intermediate in the synthesis of prostaglandins. Reversing the Baeyer-Villiger rearrangement gives cyclobutanone (17) which is the adduct from ketene and cyclopentadiene. In practice, dichloroketene is much easier to make and handle than ketene itself so compound (8) is used as an intermediate, the chlorine atoms being removed with zinc. ... 

Both the Baeyer-Villiger and the Beckmann rearrangement are used on the cyclobutanones formed in these cycloadditions. Dechlorination of adduct 12 with zinc and rearrangement with a peroxy-acid gives a lactone 25 widely used in prostaglandin synthesis.5 Note that the more substituted carbon migrates and does so with retention of configuration. 

Trost also found that treatment of these cyclobutanones with sodium methoxide and diphenyl disulfide leads to in situ bisulfenylation and ring cleavage (secosulfenylation). This was applied to the total synthesis of verrucarol, a complex tetrahydrochromanone substituted at the ring junction by a hydroxymethyl substituent. The synthetic strategy twice used the cyclobutanone formation from 1-lithiocyclo-propyl phenyl sulfide and a ketone, followed by the secosulfenylation process and Baeyer-Villiger type rearrangement of cyclobutanone. Only this part of the synthesis is described in Scheme 28. 

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