An efficient synthesis of dihydro- and tetrahydropyrans via oxonium-ene cyclization reaction.
Bondalapati, Somasekhar; Reddy, Udagandla C.; Saha, Pipas; Saikia, Anil K.; Organic & biomolecular chemistry 9 (2011) 3428–3438; doi:10.1039/c1ob00033k

data_7151845
_publ_section_title
;
 An efficient synthesis of dihydro- and tetrahydropyrans via
 oxonium-ene cyclization reaction.
;
_journal_issue                   9
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              3428
_journal_page_last               3438
_journal_paper_doi               10.1039/c1ob00033k
_journal_volume                  9
_journal_year                    2011
_chemical_formula_moiety         'C19 H20 N2 O4'
_chemical_formula_sum            'C19 H20 N2 O4'
_chemical_formula_weight         340.37
_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                 100.451(7)
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   11.6207(12)
_cell_length_b                   19.274(2)
_cell_length_c                   16.3163(15)
_cell_measurement_reflns_used    1395
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      13.12
_cell_measurement_theta_min      2.37
_cell_volume                     3593.9(6)
_computing_cell_refinement       'Bruker SMART'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SAINT'
_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      296(2)
_diffrn_measured_fraction_theta_full 1.00
_diffrn_measured_fraction_theta_max 1.00
_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  0.0857
_diffrn_reflns_av_sigmaI/netI    0.0649
_diffrn_reflns_limit_h_max       15
_diffrn_reflns_limit_h_min       -15
_diffrn_reflns_limit_k_max       25
_diffrn_reflns_limit_k_min       -25
_diffrn_reflns_limit_l_max       21
_diffrn_reflns_limit_l_min       -21
_diffrn_reflns_number            17415
_diffrn_reflns_theta_full        27.77
_diffrn_reflns_theta_max         27.77
_diffrn_reflns_theta_min         1.65
_exptl_absorpt_coefficient_mu    0.089
_exptl_absorpt_correction_T_max  0.975
_exptl_absorpt_correction_T_min  0.963
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   multi-scan
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.258
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       Needle
_exptl_crystal_F_000             1440
_exptl_crystal_size_max          0.42
_exptl_crystal_size_mid          0.35
_exptl_crystal_size_min          0.28
_refine_diff_density_max         0.146
_refine_diff_density_min         -0.188
_refine_diff_density_rms         0.035
_refine_ls_extinction_method     none
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_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     453
_refine_ls_number_reflns         8475
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.003
_refine_ls_R_factor_all          0.0988
_refine_ls_R_factor_gt           0.0522
_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^)+(0.0768P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1180
_refine_ls_wR_factor_ref         0.1411
_reflns_number_gt                6487
_reflns_number_total             8475
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c1ob00033k.txt
_cod_data_source_block           somu-231
_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 1555 2011-01-17 13:19:09Z saulius 
;
_cod_original_cell_volume        3593.8(6)
_cod_original_sg_symbol_H-M      P2(1)/n
_cod_database_code               7151845