Diones, reactions with Grignard reagents

The nucleophilic reaction of Grignard reagents with azetidin-2,3-dione 270 yielded mainly fA-3-hydroxyazetidin-2-ones 271 (Equation 76) <2006S115>. A regio- and stereoselective reaction of azetidine-2,3-dione 272 with an organoindium compound led to the formation of azetidin-2-one-tethered homoallylic alcohol 273 (Equation 77), which has been used as precursor of spirocyclic azetidin-2-ones <2004TL6429>. 

The Diels-Alder adduct of furan and maleic anhydride reacts with Grignard reagents to form lactones, which are converted to butenolides in a thermal cycloreversion reaction. Work continues on the synthesis of 4-ylidenebutenolides using the Wittig reaction on substituted maleic anhydrides the products have been converted into cyclopentene-l,3-diones. ... 

Cyclopentane-l,2-dione can be transformed in good yield into its isobutyl mono-enol ether in the same way as the 1,3 dione reaction of the free ketone group with Grignard reagents followed by dehydration of the intermediate carbinol constitutes a general synthesis of 2-alkyl-cyclopentenones... 

Copper-mediated 1,4-addition of Grignard reagent (83) to hexahydro-pyrido[l,2-c][l,3]oxazine-l,6-dione (82) afforded perhydro derivatives (84) (93JA8851). Reaction of 1,6-dione (84) with LDA and A-(5-chloro-2-pyridyl)triflimide gave vinyltriflate (81), which contained 10% of the regio-isomeric l,3,4,4a,7,8-hexahydro derivative (93JA8851). 

Alkynyltrialkylborates are versatile intermediates to 1,4-dikelones and y-oxo-esters, -nitriles, and -alkynes, as well as substituted ketones. A route from a -unsaturated cycloalkenones to 1,4-diketones is available wherein an aldehyde undergoes photoaddition to the alkene unit, and a variety of 1,4-diones is obtained by thiazolium salt-catalysed addition of aldehydes to but-2-enone. Monoacetalized 1,4-diketones and y-keto-aldehydes are formed on reaction of acyl chlorides with the Grignard reagents (13) and (14), respectively. 

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