Versatile One‐Pot Synthesis of 3‐Alkenylcoumarins

Abstract

A variety of 2-acyl-, 2-aroyl-and 2-formyl-substituted phenols are converted in a one-pot reaction with α,β-unsaturated carboxylic acid chlorides into the corresponding 3-alkenylcoumarins. Especially the labile 3-vinylcoumarins are readily available by the simple to perform protocol. If longer alkenyl chains are involved in position 3, small molecules with excel-

Convenient Synthesis of 3-Vinyl and 3-Styryl Coumarins

“…γ-Deprotonation of 3a was easily accomplished on treatment with potassium carbonate, and 2a was obtained in a satisfying yield (Scheme 1 , pathway C). 17 Although considered labile intermediates in literature, 16 we were able to isolate the vinyl coumarins in good yields. Reaction conditions and yields are presented in Table 1.…”

“…A more versatile synthesis of 3-alkenylcoumarins was achieved by a variety of 2-acyl-, 2-aroyl-, and 2-formylsubstituted phenols on reaction with R,β-unsaturated carboxylic acid chlorides. 17 Here we report a more expeditious synthesis of 3-vinyl and 3-styryl coumarin fluorescent dyes from readily available substrates. When 3-butenoic acid was allowed to react with N, N 0 -dicyclohexylcarbodiimide (DCC) the corresponding intermediate was then coupled to salicylaldehyde in the presence of 4-N,N 0 -dimethylaminopyridine (DMAP) to give 2-formylaryl but-3-enoate (1a).…”

“…The first report on the synthesis of 3-vinylcoumarin was a multistep sequence. A more versatile synthesis of 3-alkenylcoumarins was achieved by a variety of 2-acyl-, 2-aroyl-, and 2-formyl-substituted phenols on reaction with α,β-unsaturated carboxylic acid chlorides . Here we report a more expeditious synthesis of 3-vinyl and 3-styryl coumarin fluorescent dyes from readily available substrates.…”

Convenient Synthesis of 3‐Cinnamoyl‐2‐styrylchromones: Reinvestigation of the Baker–Venkataraman Rearrangement

“…In the course of reaction, deprotonation at the γ-position of ester 5 will proceed faster than the BakerVenkataraman rearrangement and lead exclusively to the formation of 3-alkenyl-5-hydroxycoumarins. [17] …”

A Facile Synthesis of Highly Functionalized 4-Arylcoumarins via Kostanecki Reactions Mediated by DBU

“…We then evaluated the same strategy using several 2-acyloxybenzophenone derivatives, aiming to synthesize 3,4-difunctionalized coumarins. It is interesting to note that the synthesis of 3,4-difunctionalized coumarins has rarely been investigated up to date, except for few examples [ 26 , 27 ]. They frequently require expensive catalysts, laborious multi-step procedures, and long reaction times.…”