Selective radical cascade (4+2) annulation with olefins towards the synthesis of chroman derivatives via organo-photoredox catalysis was written by Guan, Zhipeng;Zhong, Xingxing;Ye, Yayu;Li, Xiangwei;Cong, Hengjiang;Yi, Hong;Zhang, Heng;Huang, Zhiliang;Lei, Aiwen. And the article was included in Chemical Science in 2022.Category: ethers-buliding-blocks The following contents are mentioned in the article:
Here a new (4 + 2) radical annulation approach for the construction of these functional six-membered frameworks I (R = ethoxycarbonyl, N-methyl-N-phenylcarbamoyl, benzenesulfonyl, (2,2,6,6-tetramethylpiperidin-1-yl)carbonyl, etc.; R1 = H, Me, methoxycarbonyl; R2 = H, Me, OMe; R3 = H, F, Ph, 2,2-dichlorocyclopropyl, etc.; R2R3 = -CH=CH-CH=CH-; R4 = H, Me, OMe, CF3; R5 = H, Me;) via photocatalysis was reported. Featuring mild reaction conditions, the protocol allows readily available N-hydroxyphthalimide esters II and electron-deficient olefins RCH=CHR1 to be converted into a wide range of valuable chromans I in a highly selective manner. Moreover, the present strategy can be used in the late-stage functionalization of natural product derivatives and biol. active compounds, which demonstrated the potential application. This method is complementary to the traditional Diels-Alder [4 + 2] cycloaddition reaction of ortho-quinone methides II and electron-rich dienophiles, since electron-deficient dienophiles were smoothly transformed into the desired chromans I. This study involved multiple reactions and reactants, such as 4-Benzyloxyphenol (cas: 103-16-2Category: ethers-buliding-blocks).
4-Benzyloxyphenol (cas: 103-16-2) belongs to ethers. Esters are widespread in nature and are widely used in industry. In nature, fats are in general triesters derived from glycerol and fatty acids. Esters are responsible for the aroma of many fruits, including apples, durians, pears, bananas, pineapples, and strawberries. Esters contain a carbonyl center, which gives rise to 120° C–C–O and O–C–O angles. Unlike amides, esters are structurally flexible functional groups because rotation about the C–O–C bonds has a low barrier. Their flexibility and low polarity is manifested in their physical properties; they tend to be less rigid (lower melting point) and more volatile (lower boiling point) than the corresponding amides. Category: ethers-buliding-blocks
Referemce:
Ether – Wikipedia,
Ether | (C2H5)2O – PubChem