- Lewis acid-catalyzed annulative partial dimerization of 3-aryloxyacrylates to 4-arylchroman-2-ones: Synthesis of analogues of tolterodine, RORγ inhibitors and a GPR40 agonist
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A beguiling annulative partial dimerization of 3-aryloxyacrylates to 4-arylchroman-2-ones catalyzed by Lewis acid (BF3·OEt2) has been developed. The reaction involves two molecules of 3-aryloxyacrylate, resulting in the loss of one propiolate molecule to furnish 4-arylchroman-2-one, an important structural motif found in many natural products. This methodology has been elaborated to synthesize analogues of tolterodine, RORγ inhibitors and a GPR40 agonist.
- Kunkalkar, Rupesh A.,Fernandes, Rodney A.
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supporting information
p. 2313 - 2316
(2019/02/27)
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- Photocyclization reactions of N-substituted 3-(2- hydroxynaphthalen-1-yl) propenamide derivatives accompanied by liberation of aliphatic and aromatic primary amines
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(E)-3-(2-Hydroxynaphthalen-1-yl)propenoyl- and (E)-3-(2- hydroxynaphthalen-1-yl)-2-methylpropenoyl-protected aliphatic and aromatic primary amines were synthesized and their photolytic behavior in methanol was explored. The results showed that irradiation of the hydroxynaphthylpropenamide derivatives in a protic polar solvent at wavelengths greater than 280 nm or 340 nm causes rather efficient deprotection reactions to afford the desired amines quantitatively along with fluorescent benzocoumarins.
- Watanabe, Koh,Takahashi, Shun,Yoshizawa, Takuya,Igarashi, Tetsutaro,Sakurai, Tadamitsu
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p. 1503 - 1514
(2014/07/07)
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- Synthesis of fused furans by gas-phase pyrolysis of 2-allyloxyaryl-propenoic esters
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Flash vacuum pyrolysis of 2-allyloxypropenoic esters (e.g. 7) gives benzo[b]furans (e.g. 32) in synthetically useful yields by sequential generation of a phenoxyl radical, cyclisation and ejection of the carboxylic ester function as a free radical leaving group. The method is compatible with a range of substituents on either the benzene ring or the propenoate chain, and is particularly effective for 2-substituted benzo[b]furans. The natural products 5-methoxybenzo[b]furan 1 and angelicin 2 have been synthesised in three and four steps respectively from commercially available starting materials by this route. Related cyclisations to give naphtho[2,1-b]furan 40 were complicated by competitive formation of naphtho[2,1-b]pyran-3-ones (e.g. 41 and 42), but the yield of the required product could be optimised by the choice of the radical precursor. Annelation of a furan ring onto a thlophene is also possible by this method, but lower yields are obtained in such pyrolyses.
- Black, Michael,Cadogan,McNab, Hamish,MacPherson, Andrew D.,Roddam, V. Peter,Smith, Carol,Swenson, Helen R.
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p. 2483 - 2493
(2007/10/03)
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