Regio- and Diastereoselective Synthesis of Dihydropyrans and Pyranopyrans via Oxonium-Ene Reaction of β-Allenols and Aldehydes.
Devi, Ngangbam Renubala; Sultana, Sabera; Borah, Madhurjya; Saikia, Anil K.; The Journal of organic chemistry 83 (2018) 14987–14998; doi:10.1021/acs.joc.8b02244

data_4034729
_publ_section_title
;
 Regio- and Diastereoselective Synthesis of Dihydropyrans and Pyranopyrans
 via Oxonium-Ene Reaction of \b-Allenols and Aldehydes.
;
_journal_issue                   24
_journal_name_full               'The Journal of organic chemistry'
_journal_page_first              14987
_journal_page_last               14998
_journal_paper_doi               10.1021/acs.joc.8b02244
_journal_volume                  83
_journal_year                    2018
_chemical_formula_sum            'C28 H30 O6'
_chemical_formula_weight         462.52
_space_group_IT_number           14
_space_group_name_Hall           '-P 2ybc'
_space_group_name_H-M_alt        'P 1 21/c 1'
_symmetry_cell_setting           monoclinic
_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                 103.251(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   12.2759(7)
_cell_length_b                   11.3397(6)
_cell_length_c                   17.9816(10)
_cell_measurement_reflns_used    6130
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      23.9250
_cell_measurement_theta_min      3.7090
_cell_volume                     2436.5(2)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      296(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_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  0.0416
_diffrn_reflns_av_sigmaI/netI    0.0278
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -14
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       21
_diffrn_reflns_limit_l_min       -21
_diffrn_reflns_number            25904
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         25.00
_diffrn_reflns_theta_min         1.70
_exptl_absorpt_coefficient_mu    0.088
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.261
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             984
_exptl_crystal_size_max          0.21
_exptl_crystal_size_mid          0.17
_exptl_crystal_size_min          0.15
_refine_diff_density_max         0.199
_refine_diff_density_min         -0.317
_refine_diff_density_rms         0.078
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.084
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     309
_refine_ls_number_reflns         4291
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.084
_refine_ls_R_factor_all          0.0703
_refine_ls_R_factor_gt           0.0521
_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          0.1435
_refine_ls_wR_factor_ref         0.1590
_reflns_number_gt                3152
_reflns_number_total             4291
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            jo8b02244_si_003.cif
_cod_data_source_block           rb-cy-co2me-1
_cod_depositor_comments
;
The following automatic conversions were performed:

data item '_symmetry_cell_setting' value 'Monoclinic' was changed to
'monoclinic' in accordance with the
/home/data/users/saulius/crontab/automatic-downloads/current/ACS/lib/dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.2 last updated on
2011-04-26.

Automatic conversion script
Id: cif_fix_values 6909 2019-04-08 15:41:33Z antanas 
;
_cod_original_sg_symbol_H-M      P2(1)/c
_cod_database_code               4034729