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Acta Cryst. (2008). E64, o530 [ doi:10.1107/S1600536808002651 ]

(2S,4'R,5'R)-(E)-tert-Butyl 2-acetyl-2-(2-oxo-5-phenyl-1,3-dioxolan-4-ylmethyl)-5-phenylpent-4-enoate

D. J. Fox, D. S. Pedersen and S. Warren

Key indicators

Single-crystal X-ray study
T = 200 K
Mean (C-C) = 0.012 Å
R factor = 0.081
wR factor = 0.256
Data-to-parameter ratio = 6.6

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT022_ALERT_3_A Ratio Unique / Expected Reflections too Low ....       0.71

Author Response: The data are 91 % complete to theta_full 20.8 deg (equivalent to ca 1 angstrom resolution). 71% completeness refers to the stated theta_max of 24.87 deg. There are few observable data between 20.8 deg and 24.87 deg. i.e. the "missing" data are barely observable and the structure is not in doubt.

PLAT027_ALERT_3_A _diffrn_reflns_theta_full (too) Low ............      20.81 Deg.

Author Response: A combination of relatively thin plates and large unit-cell volume gave rise to relatively weak diffraction. It is stated clearly in the text that the resulting structure is of low precision.

PLAT029_ALERT_3_A _diffrn_measured_fraction_theta_full Low .......       0.91

Author Response: as above.


Alert level B
PLAT230_ALERT_2_B Hirshfeld Test Diff for    C15    -   C16     ..       8.27 su   
PLAT340_ALERT_3_B Low Bond Precision on C-C Bonds (x 1000) Ang ...         12      

Alert level C
ABSTM02_ALERT_3_C  The ratio of expected to reported Tmax/Tmin(RR') is < 0.90
            Tmin and Tmax reported:      0.817     0.996
            Tmin(prime) and Tmax expected:      0.969     0.996
            RR(prime) =      0.843
            Please check that your absorption correction is appropriate.
DIFMN02_ALERT_2_C  The minimum difference density is < -0.1*ZMAX*0.75
            _refine_diff_density_min given =     -0.684
            Test value =     -0.600
DIFMN03_ALERT_1_C  The minimum difference density is < -0.1*ZMAX*0.75
            The relevant atom site should be identified.
DIFMX01_ALERT_2_C  The maximum difference density is > 0.1*ZMAX*0.75
            _refine_diff_density_max given =      0.638
            Test value =      0.600
DIFMX02_ALERT_1_C  The maximum difference density is > 0.1*ZMAX*0.75
            The relevant atom site should be identified.
RFACR01_ALERT_3_C  The value of the weighted R factor is > 0.25
            Weighted R factor given   0.256
PLAT061_ALERT_3_C Tmax/Tmin Range Test RR' too Large .............       0.84      
PLAT084_ALERT_2_C High R2 Value ..................................       0.26      
PLAT089_ALERT_3_C Poor Data / Parameter Ratio (Zmax .LT. 18) .....       6.59      
PLAT097_ALERT_2_C Maximum (Positive) Residual Density ............       0.64 e/A   
PLAT098_ALERT_2_C Minimum (Negative) Residual Density ............      -0.68 e/A   
PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for        C16     
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        C15     
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        C24     
PLAT369_ALERT_2_C Long   C(sp2)-C(sp2) Bond  C17    -   C18    ...       1.55 Ang. 

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           24.87
           From the CIF: _reflns_number_total               1806
           Count of symmetry unique reflns         2557
           Completeness (_total/calc)             70.63%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured         0
           Fraction of Friedel pairs measured     0.000
           Are heavy atom types Z>Si present         no
PLAT791_ALERT_1_G Confirm the Absolute Configuration of C2     ...          S      
PLAT791_ALERT_1_G Confirm the Absolute Configuration of C4     ...          R      
PLAT791_ALERT_1_G Confirm the Absolute Configuration of C5     ...          R      
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          1      

   3 ALERT level A = In general: serious problem
   2 ALERT level B = Potentially serious problem
  15 ALERT level C = Check and explain
   5 ALERT level G = General alerts; check

   5 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
  10 ALERT type 2 Indicator that the structure model may be wrong or deficient
   9 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check