- BICYCLOPENTANOID SESQUITERPENES. THE SYNTHESIS OF CEDRANOID SESQUITERPENES VIA THE PHOTO-REARRANGEMENT OF BICYCLOOCTENONES
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(+/-)-exo-2,6,6-Trimethyltricyclo1,5>undecane-8,10-dione (11) has been synthesized from dimethyl 6,6-dimethyl-5-oxobicyclooct-7-ene dicarboxylate (17).This constitutes a new synthesis of cedrol (3) since 11 has previously been co
- Yates, Peter,Stevens, K. E.
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- Direct hydroxylation of benzene and aromatics with H2O2 catalyzed by a self-assembled iron complex: Evidence for a metal-based mechanism
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An iminopyridine Fe(ii) complex, easily prepared in situ by self-assembly of cheap and commercially available starting materials (2-picolylaldehyde, 2-picolylamine, and Fe(OTf)2 in a 2 : 2 : 1 ratio), is shown to be an effective catalyst for the direct hydroxylation of aromatic rings with H2O2 under mild conditions. This catalyst shows a marked preference for aromatic ring hydroxylation over lateral chain oxidation, both in intramolecular and intermolecular competitions, as long as the arene is not too electron poor. The selectivity pattern of the reaction closely matches that of electrophilic aromatic substitutions, with phenol yields and positions dictated by the nature of the ring substituent (electron-donating or electron-withdrawing, ortho-para or meta-orienting). The oxidation mechanism has been investigated in detail, and the sum of the accumulated pieces of evidence, ranging from KIE to the use of radical scavengers, from substituent effects on intermolecular and intramolecular selectivity to rearrangement experiments, points to the predominance of a metal-based SEAr pathway, without a significant involvement of free diffusing radical pathways.
- Capocasa, Giorgio,Olivo, Giorgio,Barbieri, Alessia,Lanzalunga, Osvaldo,Di Stefano, Stefano
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p. 5677 - 5686
(2017/12/07)
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- Improved oxidation of aromatic and aliphatic hydrocarbons using rate enhancing variants of P450Bm3 in combination with decoy molecules
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Enzyme performance can be improved using decoy molecules or engineered variants to accelerate the activity without affecting selectivity. Here we combine a rate accelerator variant of cytochrome P450Bm3 with decoy molecules to enhance the oxidation activity of a range of small organic molecules. This combined approach offers superior biocatalytic efficiency without modifying the product distribution.
- Munday, Samuel D.,Shoji, Osami,Watanabe, Yoshihito,Wong, Luet-Lok,Bell, Stephen G.
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supporting information
p. 1036 - 1039
(2016/01/16)
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- Bicyclopentanoid sesquiterpenes. The synthesis of cedranoid sesquiterpenes via the photo-rearrangement of bicyclo[2.2.2]octenones
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(±) - exo - 2,6,6 - Trimethyltricyclo[5.3.1.01.5]undecanc - 8,10 - dione (11) has been synthesized from dimethyl 6,6 - dimethyl - 5 - oxobicyclo[2.2.2]oct - 7 - ene dicarboxylate (17). This constitutes a new synthesis of cedrol(3) since 11 has previously been converted to this compound.
- Yates, Peter,Stevens
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p. 4401 - 4410
(2014/12/10)
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- Bicyclopentanoid sesquiterpenes. the synthesis of cedranoid sesquiterpenes via the photo-rearrangement of bicyclo[2.2.2]octenones
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(±) - exo - 2,6,6 - Trimethyltricyclo[5.3.l.01,5)undecane - 8,10 - dione (11) has been synthesized from dimethyl 6,6 - dimethyl - 5 - oxobicyclo[2.2.2]oct - 7 - ene dicarboxylate (17). This constitutes a new synthesis of cedrol (3) since 11 has previously been converted to this compound.
- Yates, Peter,Stevens
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p. 4401 - 4410
(2015/01/09)
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- THE TYPE A ZWITTERION IN CYCLOHEXADIENONE PHOTOCHEMISTRY: CHEMICAL TRAPPING AND STEREOCHEMISTRY
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Irradiation of 4-methyl-4-trichloromethylcyclohexa-2,5-dienone in the presence of cyclopentadiene gives two 1:1 adducts whose structures demonstrate the intermediacy of the type A zwitterion and whose stereochemistry shows that the walk rearrangement to the lumiketone proceeds with inversion of configuration.
- Samuel, Christopher J.
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p. 736 - 740
(2007/10/02)
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