An Approach to the 9-Oxo-10-oxabicyclo[5.3.0]dec-2-ene Core of the Guaianolide and Pseudoguaianolide Sesquiterpenes via a Domino Electrocyclic Ring-Opening/Carboxylic Acid Trapping of a gem-Dibromocyclopropane.
Kim, Simon J.; Lough, Alan J.; Batey, Robert A.; The Journal of organic chemistry 83 (2018) 13799–13810; doi:10.1021/acs.joc.8b02081

data_4034886
_publ_section_title
;
 An Approach to the 9-Oxo-10-oxabicyclo[5.3.0]dec-2-ene Core of the
 Guaianolide and Pseudoguaianolide Sesquiterpenes via a Domino
 Electrocyclic Ring-Opening/Carboxylic Acid Trapping of a
 gem-Dibromocyclopropane.
;
_journal_issue                   22
_journal_name_full               'The Journal of organic chemistry'
_journal_page_first              13799
_journal_page_last               13810
_journal_paper_doi               10.1021/acs.joc.8b02081
_journal_volume                  83
_journal_year                    2018
_chemical_formula_moiety         'C8 H9 Br O2'
_chemical_formula_sum            'C8 H9 Br O2'
_chemical_formula_weight         217.06
_space_group_crystal_system      monoclinic
_space_group_IT_number           14
_space_group_name_Hall           '-P 2ybc'
_space_group_name_H-M_alt        'P 1 21/c 1'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2014/7
_cell_angle_alpha                90
_cell_angle_beta                 97.883(2)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   8.6931(6)
_cell_length_b                   10.0516(7)
_cell_length_c                   9.0312(7)
_cell_measurement_reflns_used    5235
_cell_measurement_temperature    150(2)
_cell_measurement_theta_max      27.54
_cell_measurement_theta_min      2.37
_cell_volume                     781.69(10)
_computing_cell_refinement       APEX2
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_computing_structure_solution    'SHELXT (Sheldrick, 2015a)'
_diffrn_ambient_temperature      150(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Bruker Kappa APEX-DUO CCD'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0276
_diffrn_reflns_av_unetI/netI     0.0215
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 0.999
_diffrn_reflns_limit_h_max       11
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_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -13
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_diffrn_reflns_limit_l_min       -11
_diffrn_reflns_number            8709
_diffrn_reflns_point_group_measured_fraction_full 1.000
_diffrn_reflns_point_group_measured_fraction_max 0.999
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         27.545
_diffrn_reflns_theta_min         2.365
_diffrn_source                   'sealed tube with Bruker Triumph monochromator'
_exptl_absorpt_coefficient_mu    5.200
_exptl_absorpt_correction_T_max  0.7456
_exptl_absorpt_correction_T_min  0.5333
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS (Bruker, 2014)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.844
_exptl_crystal_description       plate
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_exptl_crystal_size_mid          0.230
_exptl_crystal_size_min          0.100
_refine_diff_density_max         0.337
_refine_diff_density_min         -0.430
_refine_diff_density_rms         0.070
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.079
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     100
_refine_ls_number_reflns         1800
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.079
_refine_ls_R_factor_all          0.0233
_refine_ls_R_factor_gt           0.0176
_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^)+(0.0221P)^2^+0.2673P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0438
_refine_ls_wR_factor_ref         0.0460
_reflns_Friedel_coverage         0.000
_reflns_number_gt                1586
_reflns_number_total             1800
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            jo8b02081_si_003.cif
_cod_data_source_block           d16140
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_database_code               4034886
_shelx_shelxl_version_number     2014/7
_shelx_estimated_absorpt_t_min   0.334
_shelx_estimated_absorpt_t_max   0.624
_shelx_res_checksum              38813
_shelx_hkl_checksum              86058