Novel diastereoisomers of C21H20O3 obtained from the cathodic reduction of methyl (2E)-3-[2-(2-{2[(1E)-3-methoxy-3-oxoprop-1-en-1-yl] phenyl} ethyl) phenyl]prop-2-enoate

作者：Curilazo Ricardo; Pardini Vera L; Viertler Hans; Zukerman Schpector Julio^*; Tiekink Edward R T^*

来源：Zeitschrift fur Kristallographie-Crystalline Materials, 2017, 232(11): 781-788.

DOI：10.1515/zkri-2017-2053

• conformation
• crystal structure analysis
• diastereoisomers
• Intramolecular electrohydrocyclisation
• X-ray diffraction

The diastereoisomeric title compounds, 5 and 6, were obtained as a result of intramolecular electrohydrocyclisation of methyl (2E)-3-[2-(2-{2-[(1E)-3-methoxy-3oxoprop- 1-en-1-yl] phenyl} ethyl) phenyl] prop-2-enoate. The common feature of the molecular structures is the presence of a central, eight-membered, -C(H)-C(H)-C - C-(CH2)(2)-C - C, ring appended to a cyclopentenyl and two phenyl rings. This study represents an unprecedented structural characterisation of such an atomic/bonding arrangement. The distinctive feature of the structures relates to the conformation of the central rings, i.e. approximating a boat in 5 and a chair in 6. This difference in molecular conformations arises from the different configurations at the methine-C atoms of the cyclopentenyl ring, i.e. R-and S-(or S-and R-) in 5 as opposed to R-and R-(or S-and S-) in 6. In each case, the hydroxyl-OH forms an intramolecular hydrogen-bond to the adjacent carbonyl-O atom so the molecular packing in each of 5 and 6 is sustained by non-conventional interactions. A three-dimensional architecture in 5 arises from a combination of phenyl-C-H center dot center dot center dot O(carbonyl) and methyl-and methylene-C-H center dot center dot center dot pi contacts. In the crystal of 6, supramolecular chains with a zig-zag topology along the c-axis are formed via methyl-C-H center dot center dot center dot O(hydroxyl); the chains pack with no directional interactions between them.

• 出版日期2017-11