Synthesis of Parvisoflavones A and B.

Total Synthesis of the Pyranoisoflavone Kraussianone 1 and Related Isoflavones

“…The Suzuki−Miyaura cross-coupling of 3-iodochromone 5 with boronic acid 6 using a heterogeneous Pd(C) catalyst , and subsequent cleavage of the MOM protecting groups with HCl furnished the pyranoisoflavone 4 in 72% yield. Base-catalyzed condensation of the pyranoisoflavone 4 with prenal gave the benzyl derivative of kraussianone 1, 23 (74% yield), which was finally deprotected with BCl 3 to afford kraussianone 1 ( 1 ) in 69% yield (Scheme ).…”

“…While the application of the Suzuki−Miyaura reaction in the synthesis of isoflavones was demonstrated more than two decades ago, there are not many reports on the synthesis of isoflavones with naturally occurring substitution patterns by this method, especially those with ring A possessing a phloroglucinol moiety. , Except for the pyranoisoflavone recently synthesized as a precursor to hirtellanine A, no natural pyranoisoflavones have been reported by this method. The previous synthetic procedures for pyranoisoflavones were based on the deoxybenzoin or the chalcone route, which often suffered from poor regioselectivity in the introduction of the dimethylpyran ring to the isoflavone skeleton. − We herein report the first regioselective total synthesis of kraussianone 1 ( 1 ), employing the Suzuki−Miyaura reaction as the key step for the construction of the isoflavone nucleus . This route also gave access to a structurally related antifungal pyranoisoflavone, eriosemaone D ( 2 ), , whose synthesis has not been disclosed, and to an important phytoestrogen, genistein ( 3 ).…”

Natural products possessing protein tyrosine phosphatase 1B (PTP1B) inhibitory activity found in the last decades

“…Recently, flavonoid 33 was synthesized as an inhibitor of prostate cancer and MMP-2 expression [56] . The first synthesis of other flavonoids, such as 35, 39, 40, and 45, has also been reported [40,[57][58][59] (Figure 2). Abyssinoflavanones V-VII 46-48, together with sigmoidins A-C 49-51, F 52, abyssinins I 53, II 44, 5-deoxyabyssinin II 54, 3'-prenylnarringenin 55, abyssinone-VI 56, licoagrochalcone A 57 [49] , flavonoids 58-73 [50] , flavanones 74-79 with a dihydrofuran moiety, erylatissin C 80, abyssinin III 81 [51] , and flavanones 82-93 [52] were isolated from the stem bark of E abyssinica.…”

Organolead-mediated arylation of allyl β-keto esters: selective synthesis of 2′-hydroxyisoflavones

“…The 3-(allyloxycarbonyl)chroman-4-ones were isolated as specified. (14), 276 (7), 263 (lo), 235 (7), 206 (20), 191 (9), 178 (16), 163 (7), 151 (6), 122 (3), 107 (7) (25), 263 (lo), 250 (12), 235 (20), 225 (33,206 (33, 191 (20), 178 (26), 163 (13), 137 (12), 45 (100) and 41 (27).…”