An Enantioselective Synthesis of the Epoxyquinol (+)‐Isoepiepoformin

Abstract

The epoxyquinol natural product (+)‐isoepiepoformin (1) has been synthesized for the first time and in an unambiguous fashion by using the scalemic cis‐1,2‐dihydrocatechol 2 as starting material. The spectroscopic data derived from the synthetic sample of compound 1 match those reported in the literature for the natural product and thereby confirm the structure assigned to the latter.

Chlorinated Polyketide Obtained from aDaldiniasp. Treated with the Epigenetic Modifier Suberoylanilide Hydroxamic Acid

“…The relative configuration of 2 was established as 2,3- cis /3,4- cis by comparing the J 2,3 (2.6 Hz) and J 3,4 (4.1 Hz) coupling values with coupling constants for other cyclohexanone oxides ( Table S1 ). 15 − 29 This conclusion was also supported by ROESY correlations between H-2 and H-3 and between H-3 and H-4 (Figure 2 ). DFT calculations (ECD and specific rotation) were performed to determine the absolute configuration of 2 .…”

“…The small J 2,3 (3.8 Hz) and J 3,4 (2.1 Hz) coupling constant values supported a 2,3- cis /3,4- cis relative configuration based on comparisons of these data with those for other similarly substituted cyclohexanones (Table S1). − The ROESY correlations between H-2 and OH-3, H-4 and OH-3, and H-3 and OH-2, as well as the NOE enhancement of H-2 and H-4 upon irradiation of H-3, supported the presence of two interchangeable half-chair conformations, 1a and 1b , as shown in Figure . In order to determine the absolute configuration of 1 , a lowest energy conformation search was carried out in Spartan’10 using the proposed configuration 2 S ,3 S ,4 S .…”

Cycloalkenyl Halide Substitution Reactions of Enantiopure Arene cis‐Tetrahydrodiols with Boron, Nitrogen and Phosphorus Nucleophiles

“…One of the advantages of this biocatalytic process is that single biotransformations can be readily scaled up to produce large quantities (multi-grams to kilograms) of enantiopure cis-dihydrodiols 1 (e.g., R = F, Cl, Br, I). Although, a small number of cis-dihydrodiols 1 has been extensively used in the synthesis of natural products, [2][3][4] to date, their full potential in the synthesis of chiral ligands has not been realised. The current feasibility study has been carried out in this context.…”

Crystal structure and absolute configuration of (4S,5R,6S)-4,5,6-trihydroxy-3-methylcyclohex-2-enone (gabosine H)

“…Among the natural compounds, only the structure of gabosine N, (4R,5R,6R)-4,5,6-trihydroxy-2-methylcyclohex-2-enone (Tang et al 2000), has been reported. The remaining hits were mainly derivatives of other gabosines different from H or derivatives such as 5-hydroxy-4-methyl-7-oxabicyclo[4.1.0]hept-3-en-2-one (White et al, 2010), which is an epoxide with different configuration of the asymmetric carbons compared with gabosine H.…”