Unexpected tandem ylide annulation reaction for controllable synthesis of 2H-chromenes and 4H-chromenes.
Ye, Long-Wu; Sun, Xiu-Li; Zhu, Chun-Yin; Tang, Yong; Organic letters 8 (2006) 3853–3856; doi:10.1021/ol0615174

data_1506156
_publ_section_title
;
 Unexpected tandem ylide annulation reaction for controllable synthesis of
 2H-chromenes and 4H-chromenes.
;
_journal_issue                   17
_journal_name_full               'Organic letters'
_journal_page_first              3853
_journal_page_last               3856
_journal_paper_doi               10.1021/ol0615174
_journal_volume                  8
_journal_year                    2006
_chemical_formula_sum            'C16 H14 O3'
_chemical_formula_weight         254.27
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 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                 95.487(2)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   13.4544(13)
_cell_length_b                   6.9898(7)
_cell_length_c                   13.6325(13)
_cell_measurement_reflns_used    2640
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      56.014
_cell_measurement_theta_min      5.828
_cell_volume                     1276.2(2)
_computing_cell_refinement       'Bruker SMART'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SHELXTL'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.993
_diffrn_measured_fraction_theta_max 0.993
_diffrn_measurement_device_type  'CCD area detector'
_diffrn_measurement_method       'phi and omega 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  0.1296
_diffrn_reflns_av_sigmaI/netI    0.0880
_diffrn_reflns_limit_h_max       17
_diffrn_reflns_limit_h_min       -16
_diffrn_reflns_limit_k_max       8
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       17
_diffrn_reflns_limit_l_min       -13
_diffrn_reflns_number            7186
_diffrn_reflns_theta_full        27.00
_diffrn_reflns_theta_max         27.00
_diffrn_reflns_theta_min         3.00
_exptl_absorpt_coefficient_mu    0.091
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.57757
_exptl_absorpt_correction_type   empirical
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.323
_exptl_crystal_density_method    'not measured'
_exptl_crystal_F_000             536
_exptl_crystal_size_max          0.520
_exptl_crystal_size_mid          0.500
_exptl_crystal_size_min          0.480
_refine_diff_density_max         0.202
_refine_diff_density_min         -0.304
_refine_diff_density_rms         0.052
_refine_ls_extinction_coef       0.044(5)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   0.999
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     229
_refine_ls_number_reflns         2758
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      0.999
_refine_ls_R_factor_all          0.0670
_refine_ls_R_factor_gt           0.0542
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0727P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1479
_refine_ls_wR_factor_ref         0.1580
_reflns_number_gt                2045
_reflns_number_total             2758
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol0615174rom20060621_083004.cif
_cod_data_source_block           cd25490
_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_values 1715 2011-07-08 13:25:40Z adriana 
;
_cod_original_sg_symbol_H-M      P2(1)/c
_cod_database_code               1506156