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_4034728
_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            'C29 H32 O6'
_chemical_formula_weight         476.55
_space_group_IT_number           61
_space_group_name_Hall           '-P 2ac 2ab'
_space_group_name_H-M_alt        'P b c a'
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_H-M   'P b c a'
_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            8
_cell_length_a                   11.4720(5)
_cell_length_b                   17.9909(9)
_cell_length_c                   24.4226(12)
_cell_measurement_reflns_used    2098
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      22.9220
_cell_measurement_theta_min      3.8120
_cell_volume                     5040.6(4)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type  'SuperNova, Single source at offset, Eos'
_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  0.0392
_diffrn_reflns_av_sigmaI/netI    0.0514
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       18
_diffrn_reflns_limit_k_min       -21
_diffrn_reflns_limit_l_max       27
_diffrn_reflns_limit_l_min       -29
_diffrn_reflns_number            13140
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         25.00
_diffrn_reflns_theta_min         3.00
_exptl_absorpt_coefficient_mu    0.087
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.256
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             2032
_exptl_crystal_size_max          0.20
_exptl_crystal_size_mid          0.15
_exptl_crystal_size_min          0.11
_refine_diff_density_max         0.261
_refine_diff_density_min         -0.299
_refine_diff_density_rms         0.042
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.966
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     318
_refine_ls_number_reflns         4435
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.966
_refine_ls_R_factor_all          0.1097
_refine_ls_R_factor_gt           0.0637
_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^)+(0.1289P)^2^+0.6478P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1802
_refine_ls_wR_factor_ref         0.2284
_reflns_number_gt                2665
_reflns_number_total             4435
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            jo8b02244_si_005.cif
_cod_data_source_block           exp_5571
_cod_original_sg_symbol_H-M      Pbca
_cod_database_code               4034728