Stereochemistry of Photodecarboxylation and Photodecarbonylation Reactions of Aryl Esters. The Photolysis of (S)-(+)-3,5-Di-t-butylphenyl 2-Methylbutanoate

Comparisons of Photo-Fries Rearrangements of 4-Dodecylphenyl Phenylacetate and Two Structurally Related Esters in Hexane and Polyethylene Cages. How Important Are Anchoring Chains?†

“…Furthermore, the yields of BzP from DPPA are larger than those from PPA wherever a direct comparison is possible. This decarboxylation is known to be a concerted process and highly dependent on the conformation of the ester (45–48). Based on other studies of photodecarboxylation of structurally related aryl esters, the much larger yields of BzP from DPPA than from PPA and the relatively large increases that attend film stretching or increased film crystallinity cannot be attributed to a steric or electronic effect of a para dodecyl chain (45, 50).…”

Photo-Fries rearrangements of 1-naphthyl (R)-2-phenylpropanoate in poly(vinyl acetate) and ethyl acetate: influence of medium polarity and polymer relaxation on motions of singlet radical pairs

“…It is produced by a concerted extrusion of CO 2 from the excited singlet state of (R)-1 (Finnegan and Knutson 1965, 1967, Gu et al 2001, Mori et al 2003. In addition, abstraction of an H-atom by the constituents of radical pairs A and B, especially from the backbone of the PVAc polymer or from ethyl acetate, can lead to products in which a radical is attached to the polymer or solvent.…”

A Phenolic Derivative and Two Diacetylenes from Symphyotrichum subulatum

“…In conclusion, three new (1-3) and twelve known compounds (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15) were isolated from the roots of S. subulatum. The absolute configurations of 1 and 2 were not determined.…”

“…The 13 C NMR spectrum (l " Table 1) showed two ester carbonyl signals at δ 170.7 (C-4′) and 174.6 (C-1″) as well as two olefinic methine signals at δ 124.8 (C-2′) and 133.6 (C-1′). In the 1 H NMR spectrum (l " Table 1 [15]. Based on the above data, the structure of 3 was established as (E)-4-(3-acetoxyprop-1-enyl)-2-methoxyphenyl (S)-2-methylbutanoate (l " Fig.…”

“…O-caffeoylquinic acid(13) [22], methyl 4,5-di-O-caffeoyl quinate(14) [23], and 3,4,5-tri-O-caffeoylquinic acid(15) [24] is described in the Supporting Information.Asteryne A (1): light yellow oil; [α] D 25 − 5.1 (c 0.25, CH 2 Cl 2 ); UV (CH 2 Cl 2 ): λ max (log ε) = 263 (3.24), 249 (3.35), 236 (3.39), 226 (3.41) nm; IR (film): ν max = 3423 (OH), 2926, 2856, 2255 (C≡C), 1742 (C=O), 1639, 1442, 1377, 1236, 1043 cm −1 ; 1 H-NMR (CDCl 3 , 500 MHz): see l " Table 1; 13 C-NMR (CDCl 3 , 125 MHz): see l " Table 1; ESI-MS: m/z = 375.1 [M + Na] + , 377.1 [M + 2 + Na] + (35); HR-E-SI-MS: m/z = 375.1363 (calcd. for C 19 H 25 O 4 Cl+Na: 375.1340).…”