Acetyl alkyl phenyl ketone reactions

Since the rearrangement of benzoylalkyl radicals is unrelated to the production of resinous materials (instead of the anticipated dimers) in the acetyl peroxide - alkyl phenyl ketone reactions, we must look elsewhere for an explanation. Once we come to this conclusion the fact that acetophenone is isoelec-tronic with o-methylstyrene immediately becomes significant. That is, radical additions to the carbonyl oxygen of phenyl ketones will be facilitated by resonance stabilization of the adduct, just as is the case with a-methylstyrene or styrene, i.e. 

The reaction of diphenyl methylphosphonate with lithium alkoxides gives phenyl alkyl methylphosphonates even with hindered alcohols and, in the case of chiral alcohols, with high diastereoselectivity at phosphorus. [Hydroxy(pho-sphoryloxy)X, iodo]benzenes 289, prepared from reactions of iodosobenzene with phosphonic or phosphinic acids react with ketones, esters or phenyl acetylene to give esters 290. Racemic l-hydroxy-4-(3-phenoxyphenyl)butylphosphonate diethyl ester undergoes stereoselective acetylation in the presence of a lipase to... 

A variety of substituents—including alkyl, alkenyl, cyano, acetyl, and alkoxy— is tolerated at the 2 and 5 positions of the oxazole ring for these cycloadditions. Acetylenic dienophiles with alkyl, trialkylsilyl, phenyl, ester, ketone, and acetal substituents, as well as terminal alkynes, are precedented. Ab initio calculations predict a slightly higher activation energy for the cycloaddition of oxazole with acetylene compared to the oxazole-ethylene reaction. ... 

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