Carbonyl Groups Located on the Same Ring

Martin, Aromatic Hydroxyketones Preparation and Physical Properties, 

27 Aromatic Polyketones Containing At Least One Propionyl Group 

COCH2CH3 - Preparation by Fries rearrangement of p-(propionyloxy) [ ij -acetophenone with aluminium chloride (4 mol) without 

COCH3 - Also obtained by Friedel-Crafts acylation of p-hydroxy- 

COCH3 Obtained by reaction of propionic acid with resaceto-phenone (m.p. 142°) in the presence of polyphos-phoric acid [8383] for 10 min in a boiling water bath COCH2CH3 (32%) [6738]. 

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The high stereoselectivity observed in this cyclization reaction was attributed to the location of the carbonyl moiety in a rigid cyclic ring framework, allowing H-abstraction from the same face of the initially formed five-membered ring. The same group has further utilized the constraint imparted by the benzylidene acetal moiety on the excited state photoreactivity of the carbonyl moiety of the D-xylose derivative 52. Thus, 8-H-abstraction results in the formation of a diastereomeric mixture of cyclized product 53, which is further transformed into D-glucopyranose 54 and D-idopyranose 55 derivatives, as shown in Scheme 8.16 [17]. 

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