Mechanistically Inspired Route toward Hexahydro-2H-chromenes via Consecutive [4 + 2] Cycloadditions.
Ashtekar, Kumar Dilip; Ding, Xinliang; Toma, Edmond; Sheng, Wei; Gholami, Hadi; Rahn, Christopher; Reed, Paul; Borhan, Babak; Organic letters 18 (2016) 3976–3979; doi:10.1021/acs.orglett.6b01742

data_1555646
_publ_section_title
;
 Mechanistically Inspired Route toward Hexahydro-2H-chromenes via
 Consecutive [4 + 2] Cycloadditions.
;
_journal_issue                   16
_journal_name_full               'Organic letters'
_journal_page_first              3976
_journal_page_last               3979
_journal_paper_doi               10.1021/acs.orglett.6b01742
_journal_volume                  18
_journal_year                    2016
_chemical_absolute_configuration ad
_chemical_formula_moiety         'C27 H22 Cl2 O6'
_chemical_formula_sum            'C27 H22 Cl2 O6'
_chemical_formula_weight         513.34
_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
_audit_creation_date             2015-03-05
_audit_creation_method
;
Olex2 1.2-alpha
(compiled 2015.01.26 svn.r3150 for OlexSys, GUI svn.r4998)
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   7.2743(5)
_cell_length_b                   10.1737(7)
_cell_length_c                   32.241(2)
_cell_measurement_reflns_used    5214
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      25.01
_cell_measurement_theta_min      2.37
_cell_volume                     2386.0(3)
_computing_cell_refinement       'SAINT v8.34A (Bruker, 2013)'
_computing_data_collection       'COSMO (BRUKER, V1.61, 2009)'
_computing_data_reduction        'SAINT v8.34A (Bruker, 2013)'
_computing_molecular_graphics    'Olex2 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 (Dolomanov et al., 2009)'
_computing_structure_refinement  'XL (Sheldrick, 2008)'
_computing_structure_solution    'ShelXS (Sheldrick, 2008)'
_diffrn_ambient_temperature      173(2)
_diffrn_detector_area_resol_mean 836.6
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       \w
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0717
_diffrn_reflns_av_unetI/netI     0.0650
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 1.000
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       38
_diffrn_reflns_limit_l_min       -38
_diffrn_reflns_number            20039
_diffrn_reflns_point_group_measured_fraction_full 1.000
_diffrn_reflns_point_group_measured_fraction_max 1.000
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         25.373
_diffrn_reflns_theta_min         1.263
_diffrn_source                   'sealed tube'
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.314
_exptl_absorpt_correction_T_max  0.7452
_exptl_absorpt_correction_T_min  0.6515
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
'SADABS-2014/5 (Bruker,2014/5) was used for absorption correction. wR2(int) was 0.0691 before and 0.0642 after correction. The Ratio of minimum to maximum transmission is 0.8743. The \l/2 correction factor is 0.00150.'
_exptl_crystal_colour            colourless
_exptl_crystal_colour_primary    colourless
_exptl_crystal_density_diffrn    1.429
_exptl_crystal_description       needle
_exptl_crystal_F_000             1064
_exptl_crystal_recrystallization_method 'used as received'
_exptl_crystal_size_max          0.198
_exptl_crystal_size_mid          0.056
_exptl_crystal_size_min          0.025
_refine_diff_density_max         0.406
_refine_diff_density_min         -0.396
_refine_diff_density_rms         0.126
_refine_ls_abs_structure_details
;
 Flack x determined using 1142 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   -0.06(5)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.036
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     317
_refine_ls_number_reflns         4370
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.036
_refine_ls_R_factor_all          0.0719
_refine_ls_R_factor_gt           0.0462
_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^)+(0.0624P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1005
_refine_ls_wR_factor_ref         0.1237
_reflns_Friedel_coverage         0.725
_reflns_Friedel_fraction_full    1.000
_reflns_Friedel_fraction_max     0.999
_reflns_number_gt                3291
_reflns_number_total             4370
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            ol6b01742_si_003.cif
_cod_data_source_block           bb315a
_cod_database_code               1555646
_shelxl_version_number           2014/6
_shelx_estimated_absorpt_t_max   0.992
_shelx_estimated_absorpt_t_min   0.940
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups, All C(H,H) groups
 At 1.5 times of:
  All C(H,H,H) groups
2.a Ternary CH refined with riding coordinates:
 C3(H3), C4(H4), C5(H5), C8(H8), C9(H9)
2.b Secondary CH2 refined with riding coordinates:
 C2(H2A,H2B), C14(H14A,H14B)
2.c Aromatic/amide H refined with riding coordinates:
 C10(H10), C12(H12), C18(H18), C19(H19), C20(H20), C21(H21), C24(H24),
 C25(H25), C26(H26), C27(H27)
2.d Idealised Me refined as rotating group:
 C15(H15A,H15B,H15C)
;
_contact_crystallographer_email  staples@chemistry.msu.com
_contact_crystallographer_name   'Richard Staples'
_olex2_diffrn_ambient_temperature_device 'Oxford Cryosystems'
_olex2_exptl_crystal_mounting_method
'The crystal was mounted on a nylon loop with paratone oil'
_olex2_submission_original_sample_id DXL-2-81-3BB1
_olex2_submission_special_instructions 'No special instructions were received'