Electron-deficient dienes. 5. An inverse-electron-demand Diels-Alder approach to 2-substituted 4-methoxyxanthones and 3,4-dimethoxyxanthones.
Dang, Anh-Thu; Miller, David O.; Dawe, Louise N.; Bodwell, Graham J.; Organic letters 10 (2008) 233–236; doi:10.1021/ol702614b

data_1504491
_publ_section_title
;
 Electron-deficient dienes. 5. An inverse-electron-demand Diels-Alder
 approach to 2-substituted 4-methoxyxanthones and 3,4-dimethoxyxanthones.
;
_journal_issue                   2
_journal_name_full               'Organic letters'
_journal_page_first              233
_journal_page_last               236
_journal_paper_doi               10.1021/ol702614b
_journal_volume                  10
_journal_year                    2008
_chemical_formula_sum            'C22 H20 O7 S'
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_symmetry_space_group_name_Hall  '-P 1'
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_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
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_cell_length_b                   9.907(2)
_cell_length_c                   11.199(2)
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_cell_measurement_temperature    113(2)
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_cell_measurement_theta_min      1.9182
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_computing_cell_refinement       'CrystalClear (Rigaku/MSC Inc., 2005)'
_computing_data_collection       'CrystalClear (Rigaku/MSC Inc., 2005)'
_computing_data_reduction        'CrystalClear (Rigaku/MSC Inc., 2005)'
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_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      113(2)
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_diffrn_measured_fraction_theta_full 0.997
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_device_type  'Rigaku Saturn'
_diffrn_measurement_method       \w
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_diffrn_reflns_limit_k_min       -12
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_diffrn_reflns_limit_l_min       -14
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_exptl_crystal_description       Prism
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_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
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_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.107
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_refine_ls_R_factor_gt           0.0505
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0447P)^2^+0.6207P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1157
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_reflns_number_gt                4083
_reflns_number_total             4433
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol702614b-file001.cif
_cod_data_source_block           shelx1
_cod_depositor_comments
;
The following automatic conversions were performed:

'_exptl_absorpt_correction_type' value 'Numerical' changed to
'numerical' according to
/home/saulius/struct/CIF-dictionaries/cif_core.dic dictionary named
'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_values 1715 2011-07-08 13:25:40Z adriana 
;
_cod_original_cell_volume        968.4(3)
_cod_database_code               1504491