Preparation and Diels-Alder reaction of some benzoylacrylic acids

Abstract

Although Friedel-Crafts acylations of the dimethyl ethers of catechol and hydroquinone with maleic anhydride give the expected products, the reaction of the dimethyl ether of resorcinol (la) with maleic anhydride in the presence of aluminum chloride has been the source of some controversy.1 Rice2 3found that the reaction in carbon disulfide gave mainly the succinic acid 2 (cf. ref 3 for a similar result with the benzoylacrylic acid 3a as a minor product). Baddeley and co-workers4 reported conditions under which 3a was the main product.

Competent Route to Unsymmetric Dimer Architectures: Total Syntheses of (−)‐Lycodine and (−)‐Complanadines A and B, and Evaluation of Their Neurite Outgrowth Activities

“…Since the Diels–Alder reaction of diene 21 with α,β‐unsaturated ketone 22 led only led to the undesired regioisomer 23 as anticipated (Scheme ), we designed dienophile 26 a by addition of an electron‐withdrawing ester group at C8 to reverse the regioselectivity . Additionally, to facilitate NMR analysis of the Diels–Alder adducts, diene 25 was employed for the reaction instead of 21 .…”

Synthetically Important Ring-Opening Acylations of Alkoxybenzenes

“…Unsaturated substrates such as maleic anhydride have been used by Wheeler and co-workers to obtain the 4-aryl-4-oxo-2-butenoic or benzoacrylic acid, which was converted into the cyclohexenoic acid by Diels-Alder (DA) reaction with isoprene (Scheme 14). 25 When monomethoxybenzene was used, the yield of the benzoacrylic acid was only 10%. Attempts to synthesize the cyclohexene acid directly by the DA reaction of electron-rich arene with anhydride only resulted in the formation of the bridged lactones with 47% combined yield.…”