13677-74-2

Upstream product

• 1616-51-9 3-allyloxyphenol 
• 108-46-3 recorcinol 
• 37592-19-1 3-allyloxyanisole 
• 7585-39-9 β‐cyclodextrin 

Relevant academic research and scientific papers

Biomimetic Total Synthesis of Santalin Y

A biomimetic total synthesis of santalin Y, a structurally complex but racemic natural product, is described. The key step is proposed to be a (3+2) cycloaddition of a benzylstyrene to a "vinylogous oxidopyrylium", which is followed by an intramolecular F

Substituent effects on the rate constants for the photo-claisen rearrangement of allyl aryl ethers

The photochemistry of 11 substituted allyl 4-X- and 3-X-aryl ethers 3 (ArOCH2-CH=CH2) has been examined in both methanol and cyclohexane as solvents. The ethers react by the photo-Claisen rearrangement to give allyl substituted phenols as the major primary photoproducts, as expected from the well-established radical pair mechanism. The excited singlet state properties (absorption spectra, fluorescence spectra, fluorescence quantum yields, and singlet lifetimes) were compared with a parallel set of unreactive 4-X- and 3-X-anisoles 4. The excited-state properties of three substituted 4-X-aryl 4-(1-butenyl) ethers 14 (ArOCH2CH2-CH=CH2) were also examined. The model compounds 4 and the reactive allyl ethers 3 have essentially identical rate constants for the excited-state processes with the exception of khoms, the rate constant for homolytic cleavage from S1 of the allyl ethers to give the radical pair. The difference between the fluorescence quantum yields and/or singlet lifetimes for 3 and 4 were used to obtain values of khoms for all of the allyl ethers. These values exhibit a large substituent effect, spanning almost 2 orders of magnitude with electron-donating groups (CH3O, CH3) accelerating the reaction and electron-withdrawing ones (CN, CF3) slowing it down. The parallel range of rate constants observed in both methanol and cyclohexane indicates that ion pairs are not important intermediates in these rearrangements. Quantum yields of reaction (Φr) for several of the more reactive ethers demonstrate that neither these values nor rate constants of reaction (khomr) derived from them are reliable measures of the actual excited-state process. In fact, the khomr values are significantly lower than the khoms ones, indicating that the radical pairs undergo recombination to generate starting material. Finally, the khoms rate constants were found to parallel a trend for the change in bond dissociation energy (ΔBDE) for the O-C (allyl) bond of the allyl ethers, indicating that other possible substituent effects are of minor importance.

Selective deprotection of propargyl ethers using tetrathiomolybdate

Benzyltriethylammonium tetrathiomolybdate, [PhCH2NEt3]2MoS4, 1 deprotects propargyl ethers of alcohols and phenols in a selective manner in high yields. Easily reducible groups like nitro, aldehyde, keto and allyl are not affected.

MODIFICATION OF PHOTOCHEMICAL REACTIVITY BY CYCLODEXTRIN COMPLEXATION: SELECTIVITY IN PHOTO-CLAISEN REARRANGEMENT

Photorearrangements of meta-alkoxyphenylallyl ethers 1-5 in ethanol, in water and as complexes of α and β-cyclodextrins have been investigated.The ratio of the two ortho rearrangement products was dependent both on the lenght of the alkoxy substituent and on that of the host cavity suggesting that, subtle and rationale engineering manipulation is required to achieve exclusive obtention of only one ortho isomer.It is speculated that α-cyclodextrin provides a "tight fit" while β-cyclodextrin offers a "loose fit".This tightness of binding is suggested to be responsible for the selectivity among the ortho isomers with α-cyclodextrin as the host.Further, the results indicate that "loose cavity" can be tighttened by incorporating a "molecular spacer" such as a long hydrocarbon chain as an intramolecular appendix.