Synthesis of 2,3,5,6-tetrasubstituted tetrahydropyrans via (3,5)-oxonium-ene reaction.
Saha, Pipas; Bhunia, Anup; Saikia, Anil K.; Organic & biomolecular chemistry 10 (2012) 2470–2481; doi:10.1039/c2ob06832j

data_7152253
_publ_section_title
;
 Synthesis of 2,3,5,6-tetrasubstituted tetrahydropyrans via
 (3,5)-oxonium-ene reaction.
;
_journal_issue                   12
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              2470
_journal_page_last               2481
_journal_paper_doi               10.1039/c2ob06832j
_journal_volume                  10
_journal_year                    2012
_chemical_formula_sum            'C20 H26 O5'
_chemical_formula_weight         346.41
_space_group_IT_number           33
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2c -2n'
_symmetry_space_group_name_H-M   'P n a 21'
_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                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   19.8370(10)
_cell_length_b                   15.2026(8)
_cell_length_c                   6.3744(4)
_cell_measurement_reflns_used    4652
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      21.73
_cell_measurement_theta_min      2.68
_cell_volume                     1922.35(18)
_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 0.998
_diffrn_measured_fraction_theta_max 0.998
_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  0.1138
_diffrn_reflns_av_sigmaI/netI    0.0692
_diffrn_reflns_limit_h_max       21
_diffrn_reflns_limit_h_min       -23
_diffrn_reflns_limit_k_max       17
_diffrn_reflns_limit_k_min       -17
_diffrn_reflns_limit_l_max       7
_diffrn_reflns_limit_l_min       -7
_diffrn_reflns_number            16994
_diffrn_reflns_theta_full        24.74
_diffrn_reflns_theta_max         24.74
_diffrn_reflns_theta_min         1.69
_exptl_absorpt_coefficient_mu    0.085
_exptl_absorpt_correction_T_max  0.9789
_exptl_absorpt_correction_T_min  0.9585
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS (Sheldrick, 1997)'
_exptl_crystal_colour            orange
_exptl_crystal_density_diffrn    1.197
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       rod
_exptl_crystal_F_000             744
_exptl_crystal_size_max          0.40
_exptl_crystal_size_mid          0.30
_exptl_crystal_size_min          0.20
_refine_diff_density_max         0.241
_refine_diff_density_min         -0.244
_refine_diff_density_rms         0.048
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.0(18)
_refine_ls_extinction_coef       0.013(2)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_goodness_of_fit_ref   0.943
_refine_ls_hydrogen_treatment    none
_refine_ls_matrix_type           full
_refine_ls_number_parameters     231
_refine_ls_number_reflns         3185
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      0.943
_refine_ls_R_factor_all          0.0856
_refine_ls_R_factor_gt           0.0677
_refine_ls_shift/su_max          0.012
_refine_ls_shift/su_mean         0.005
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.1000P)^2^+0.3000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1644
_refine_ls_wR_factor_ref         0.1735
_reflns_number_gt                1567
_reflns_number_total             1810
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c2ob06832j.txt
_cod_data_source_block           ps-338m
_cod_database_code               7152253