Brønsted Acid-Catalyzed, Diastereo- and Enantioselective, Intramolecular Oxa-Diels-Alder Reaction of ortho-Quinone Methides and Unactivated Dienophiles.
Ukis, Rostyslav; Schneider, Christoph; The Journal of organic chemistry 84 (2019) 7175–7188; doi:10.1021/acs.joc.9b00860

data_4034581
_publ_section_title
;
 Br\/onsted Acid-Catalyzed, Diastereo- and Enantioselective,
 Intramolecular Oxa-Diels-Alder Reaction of ortho-Quinone Methides and
 Unactivated Dienophiles.
;
_journal_issue                   11
_journal_name_full               'The Journal of organic chemistry'
_journal_page_first              7175
_journal_page_last               7188
_journal_paper_doi               10.1021/acs.joc.9b00860
_journal_volume                  84
_journal_year                    2019
_chemical_absolute_configuration 'S(C7), S(C15), R(C16)'
_chemical_formula_sum            'C22 H18 O2'
_chemical_formula_weight         314.36
_space_group_crystal_system      orthorhombic
_space_group_IT_number           19
_space_group_name_Hall           'P 2ac 2ab'
_space_group_name_H-M_alt        'P 21 21 21'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-2014/7
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   5.7829(2)
_cell_length_b                   13.4141(5)
_cell_length_c                   20.7255(6)
_cell_measurement_reflns_used    78
_cell_measurement_temperature    180(2)
_cell_measurement_theta_max      24
_cell_measurement_theta_min      2
_cell_volume                     1607.73(9)
_computing_cell_refinement       'IPDS1 (Fa.STOE)'
_computing_data_collection       'IPDS1 (Fa.STOE)'
_computing_data_reduction        'IPDS1 (Fa.STOE)'
_computing_molecular_graphics    ORTEP
_computing_structure_refinement  'SHELXL-2014/7 (Sheldrick, 2014)'
_computing_structure_solution    SHELXS_2014
_diffrn_ambient_temperature      180(2)
_diffrn_measured_fraction_theta_full 0.997
_diffrn_measured_fraction_theta_max 0.991
_diffrn_measurement_device_type  'STOE STRADIVARI'
_diffrn_measurement_method       omega-scans
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54186
_diffrn_reflns_av_R_equivalents  0.0330
_diffrn_reflns_av_unetI/netI     0.0200
_diffrn_reflns_Laue_measured_fraction_full 0.997
_diffrn_reflns_Laue_measured_fraction_max 0.991
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -5
_diffrn_reflns_limit_k_max       15
_diffrn_reflns_limit_k_min       -15
_diffrn_reflns_limit_l_max       19
_diffrn_reflns_limit_l_min       -25
_diffrn_reflns_number            15919
_diffrn_reflns_point_group_measured_fraction_full 0.996
_diffrn_reflns_point_group_measured_fraction_max 0.987
_diffrn_reflns_theta_full        67.686
_diffrn_reflns_theta_max         70.611
_diffrn_reflns_theta_min         3.925
_exptl_absorpt_coefficient_mu    0.646
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.299
_exptl_crystal_description       'colourless needles'
_exptl_crystal_F_000             664
_exptl_crystal_size_max          0.200
_exptl_crystal_size_mid          0.100
_exptl_crystal_size_min          0.100
_refine_diff_density_max         0.142
_refine_diff_density_min         -0.118
_refine_diff_density_rms         0.027
_refine_ls_abs_structure_details
;
 Flack x determined using 1152 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   -0.03(14)
_refine_ls_extinction_coef       0.0012(4)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL-2014/7 (Sheldrick 2014'
_refine_ls_goodness_of_fit_ref   1.081
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     218
_refine_ls_number_reflns         3030
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.081
_refine_ls_R_factor_all          0.0298
_refine_ls_R_factor_gt           0.0283
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0518P)^2^+0.0570P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0784
_refine_ls_wR_factor_ref         0.0792
_reflns_Friedel_coverage         0.697
_reflns_Friedel_fraction_full    0.995
_reflns_Friedel_fraction_max     0.981
_reflns_number_gt                2878
_reflns_number_total             3030
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            jo9b00860_si_002.cif
_cod_data_source_block           sv0074
_cod_database_code               4034581
_shelx_shelxl_version_number     2014/7
_shelx_estimated_absorpt_t_min   0.882
_shelx_estimated_absorpt_t_max   0.938
_shelx_res_checksum              21147
_shelx_hkl_checksum              15084