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_1555647
_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         'C29 H28 O8, 2(C H2 Cl2)'
_chemical_formula_sum            'C31 H32 Cl4 O8'
_chemical_formula_weight         674.36
_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     iterative
_audit_creation_date             2015-07-27
_audit_creation_method
;
Olex2 1.2
(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                   10.9256(4)
_cell_length_b                   14.7077(4)
_cell_length_c                   19.6645(8)
_cell_measurement_reflns_used    2937
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      70.838
_cell_measurement_theta_min      3.753
_cell_volume                     3159.90(19)
_computing_cell_refinement       'SAINT v8.34A (Bruker, 2013)'
_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    'olex2.solve (Bourhis et al., 2015)'
_diffrn_ambient_temperature      173.0
_diffrn_detector_area_resol_mean 8
_diffrn_measured_fraction_theta_full 0.976
_diffrn_measured_fraction_theta_max 0.971
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0820
_diffrn_reflns_av_unetI/netI     0.0958
_diffrn_reflns_Laue_measured_fraction_full 0.976
_diffrn_reflns_Laue_measured_fraction_max 0.971
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       15
_diffrn_reflns_limit_k_min       -18
_diffrn_reflns_limit_l_max       23
_diffrn_reflns_limit_l_min       -24
_diffrn_reflns_number            15359
_diffrn_reflns_point_group_measured_fraction_full 0.972
_diffrn_reflns_point_group_measured_fraction_max 0.961
_diffrn_reflns_theta_full        67.679
_diffrn_reflns_theta_max         71.999
_diffrn_reflns_theta_min         3.753
_diffrn_source                   'sealed tube'
_exptl_absorpt_coefficient_mu    3.823
_exptl_absorpt_correction_T_max  0.7535
_exptl_absorpt_correction_T_min  0.5022
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
SADABS-2012/1 (Bruker,2012) was used for absorption correction.
wR2(int) was 0.1075 before and 0.0729 after correction.
The Ratio of minimum to maximum transmission is 0.6665.
The \l/2 correction factor is 0.0015.
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.418
_exptl_crystal_description       needle
_exptl_crystal_F_000             1400
_exptl_crystal_size_max          0.256
_exptl_crystal_size_mid          0.044
_exptl_crystal_size_min          0.043
_refine_diff_density_max         0.310
_refine_diff_density_min         -0.341
_refine_diff_density_rms         0.058
_refine_ls_abs_structure_details
;
 Flack x determined using 1380 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.028(18)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.011
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     391
_refine_ls_number_reflns         5984
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.011
_refine_ls_R_factor_all          0.0953
_refine_ls_R_factor_gt           0.0631
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0697P)^2^+0.0996P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1459
_refine_ls_wR_factor_ref         0.1646
_reflns_Friedel_coverage         0.761
_reflns_Friedel_fraction_full    0.968
_reflns_Friedel_fraction_max     0.947
_reflns_number_gt                4207
_reflns_number_total             5984
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            ol6b01742_si_002.cif
_cod_data_source_block           bb715a
_cod_database_code               1555647
_shelxl_version_number           2014/6
_shelx_estimated_absorpt_t_max   0.853
_shelx_estimated_absorpt_t_min   0.441
_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), C16(H16)
2.b Secondary CH2 refined with riding coordinates:
 C17(H17A,H17B), C21(H21A,H21B), C2S(H2SA,H2SB), C1S(H1SA,H1SB)
2.c Aromatic/amide H refined with riding coordinates:
 C7(H7), C10(H10), C11(H11), C12(H12), C13(H13), C19(H19), C25(H25), C26(H26),
 C27(H27), C28(H28)
2.d Idealised Me refined as rotating group:
 C15(H15A,H15B,H15C), C22(H22A,H22B,H22C), C29(H29A,H29B,H29C)
;
_olex2_diffrn_ambient_temperature_device 'Oxford Cryosystems'
_olex2_submission_special_instructions 'No special instructions were received'