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_7151843
_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         'C17 H21 Br O'
_chemical_formula_sum            'C17 H21 Br O'
_chemical_formula_weight         321.24
_space_group_IT_number           4
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  'P 2yb'
_symmetry_space_group_name_H-M   'P 1 21 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                 92.210(2)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   4.7575(2)
_cell_length_b                   9.8672(4)
_cell_length_c                   16.6178(6)
_cell_measurement_reflns_used    2848
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      21.50
_cell_measurement_theta_min      2.40
_cell_volume                     779.51(5)
_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 0.991
_diffrn_measured_fraction_theta_max 0.991
_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  0.1081
_diffrn_reflns_av_sigmaI/netI    0.0717
_diffrn_reflns_limit_h_max       4
_diffrn_reflns_limit_h_min       -4
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       15
_diffrn_reflns_limit_l_min       -17
_diffrn_reflns_number            5238
_diffrn_reflns_theta_full        21.60
_diffrn_reflns_theta_max         21.60
_diffrn_reflns_theta_min         1.23
_exptl_absorpt_coefficient_mu    5.198
_exptl_absorpt_correction_T_max  0.273
_exptl_absorpt_correction_T_min  0.144
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   multi-scan
_exptl_crystal_colour            Colorless
_exptl_crystal_density_diffrn    1.369
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       Flake
_exptl_crystal_F_000             331.55
_exptl_crystal_size_max          0.40
_exptl_crystal_size_mid          0.35
_exptl_crystal_size_min          0.25
_refine_diff_density_max         0.463
_refine_diff_density_min         -0.357
_refine_diff_density_rms         0.115
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -0.04(2)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.077
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     174
_refine_ls_number_reflns         1797
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.077
_refine_ls_R_factor_all          0.0605
_refine_ls_R_factor_gt           0.0525
_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^)+(0.1000P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1308
_refine_ls_wR_factor_ref         0.1449
_reflns_number_gt                963
_reflns_number_total             1797
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c1ob00033k.txt
_cod_data_source_block           fpbr-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 1555 2011-01-17 13:19:09Z saulius 
;
_cod_original_sg_symbol_H-M      'P 21 '
_cod_database_code               7151843