A Simplified Route to (E)-2-Alkylidene-1,4-diketones

Abstract

Conjugate addition of nitroalkanes to allyl Baylis-Hillman acetates 1 in the presence of NaOH (0.6 N) in THF gave 2-alkylidene-4-nitro ketones 2 with total stereoselectivity, which were further converted via the Nef reaction into the corresponding 1,4-diketones 3 in fair to good yields.

New substituted indene derivatives from bicyclic Baylis-Hillman acetate

“…Continuing with our efforts toward the functionalization of the bicyclic Baylis-Hillman acetate 2, we report herein the reactivity of the bicyclic Baylis-Hillman adduct 2b with nitroalkanes salts as nucleophilic reagents. Conjugate addition of nitroalkane to functional allyl acetates has been the subject of intensive work by our group [43][44][45][46][47] . Based on the previous results achieved by our group and others 48 , we further investigated the reactivity of allyl acetates 2b with nitronate anion generated from primary and secondary nitroalkanes toward the formation of highly substituted ethyl 1-alkylidene-1H-indene-2carboxylates 4.…”

Highly Substituted Isoxazoles:The Baylis-Hillman Reaction of Substituted 4-Isoxazolecarbaldehydesand Attempted Cyclization to Isoxazole-Annulated Derivatives

“…The stereochemistry of these products was assigned as E, based on the literature. 19 However, heating the reaction mixture for a prolonged period decreased the yield of the products as there was appreciable formation of polar impurities that were not isolated. But a mass spectrum of the mixture did indicate the presence of molecular ion peaks corresponding to acrylic acid derivatives 18c,e that may have obviously resulted due to hydrolysis of the ester in the presence of base.…”

Stereoselective Synthesis of Functionalized 1,4-Dienes

“…[4] This procedure provides a solid carbon-carbon bond-forming reaction in organic chemistry, leading to a reliable method of obtaining some biologically active compounds (a-methylene-d-valerolactones 2, [1] ( AE )-sarkomycin 3, [5] and ( AE )-mitsugashwalactone 4 [6] ) (Scheme 1).…”