The dihydrofuran template approach to furofuran synthesis.
Aldous, David J.; Batsanov, Andrei S.; Yufit, Dmitrii S.; Dalençon, Anne J; Dutton, William M.; Steel, Patrick G.; Organic & biomolecular chemistry 4 (2006) 2912–2927; doi:10.1039/b604952d

data_7151242
_publ_section_title
;
 The dihydrofuran template approach to furofuran synthesis.
;
_journal_issue                   15
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              2912
_journal_page_last               2927
_journal_paper_doi               10.1039/b604952d
_journal_volume                  4
_journal_year                    2006
_chemical_formula_moiety         'C20 H18 O6'
_chemical_formula_sum            'C20 H18 O6'
_chemical_formula_weight         354.34
_chemical_melting_point          414(1)
_chemical_name_common
;2-endo,6-endo-bis(3',4'-methylenedioxyphenyl) -3,7-dioxa-
bicyclo(3.3.0)octane
;
_chemical_name_systematic
; 2-endo,6-endo-bis(3',4'-methylenedioxyphenyl)
-3,7-dioxa-bicyclo[3.3.0]octane
;
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2yn'
_symmetry_space_group_name_H-M   'P 1 21/n 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 96.98(1)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   8.1928(10)
_cell_length_b                   7.4438(9)
_cell_length_c                   26.234(3)
_cell_measurement_reflns_used    883
_cell_measurement_temperature    120(2)
_cell_measurement_theta_max      26.13
_cell_measurement_theta_min      12.05
_cell_volume                     1588.0(3)
_computing_cell_refinement       'SMART version 5.060 (Bruker, 1999)'
_computing_data_collection       'SMART version 5.060 (Bruker, 1999)'
_computing_data_reduction        'SAINT version 6.02A (Bruker, 2001)'
_computing_molecular_graphics    'SHELXTL version 6.12 (Bruker, 2001)'
_computing_publication_material  'SHELXTL version 6.12 (Bruker, 2001)'
_computing_structure_refinement  'SHELXTL version 6.12 (Bruker, 2001)'
_computing_structure_solution    'SHELXTL version 6.12 (Bruker, 2001)'
_diffrn_ambient_temperature      120(2)
_diffrn_detector_area_resol_mean 8
_diffrn_measured_fraction_theta_full 0.995
_diffrn_measured_fraction_theta_max 0.995
_diffrn_measurement_device_type  'SMART 1K CCD area detector'
_diffrn_measurement_method       '\w scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0339
_diffrn_reflns_av_sigmaI/netI    0.0227
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       35
_diffrn_reflns_limit_l_min       -35
_diffrn_reflns_number            18649
_diffrn_reflns_theta_full        29.07
_diffrn_reflns_theta_max         29.07
_diffrn_reflns_theta_min         1.56
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.110
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.482
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             744
_exptl_crystal_size_max          0.38
_exptl_crystal_size_mid          0.28
_exptl_crystal_size_min          0.14
_refine_diff_density_max         0.400
_refine_diff_density_min         -0.268
_refine_diff_density_rms         0.060
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.088
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     235
_refine_ls_number_reflns         4226
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.088
_refine_ls_R_factor_all          0.0540
_refine_ls_R_factor_gt           0.0449
_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^)+(0.0566P)^2^+0.5918P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1117
_refine_ls_wR_factor_ref         0.1181
_reflns_number_gt                3562
_reflns_number_total             4226
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            b604952d.txt
_cod_data_source_block           (1)
_cod_depositor_comments
;
The following automatic conversions were performed:
'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
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_enum 1527 2010-12-29 10:47:43Z saulius 
;
_cod_original_sg_symbol_H-M      P2(1)/n
_cod_database_code               7151242