Meroterpenoid Synthesis via Sequential Polyketide Aromatization and Cationic Polyene Cyclization: Total Syntheses of (+)-Hongoquercin A and B and Related Meroterpenoids.
Ma, Tsz-Kan; Elliott, Daniel C.; Reid, Stephanie; White, Andrew J. P.; Parsons, Philip J.; Barrett, Anthony G. M.; The Journal of organic chemistry 83 (2018) 13276–13286; doi:10.1021/acs.joc.8b02095

data_4035746
_publ_section_title
;
 Meroterpenoid Synthesis via Sequential Polyketide Aromatization and
 Cationic Polyene Cyclization: Total Syntheses of (+)-Hongoquercin A and B
 and Related Meroterpenoids.
;
_journal_issue                   21
_journal_name_full               'The Journal of organic chemistry'
_journal_page_first              13276
_journal_page_last               13286
_journal_paper_doi               10.1021/acs.joc.8b02095
_journal_volume                  83
_journal_year                    2018
_chemical_formula_moiety         'C21 H27 Br O4'
_chemical_formula_sum            'C21 H27 Br O4'
_chemical_formula_weight         423.33
_space_group_crystal_system      triclinic
_space_group_IT_number           2
_space_group_name_Hall           '-P 1'
_space_group_name_H-M_alt        'P -1'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2014/7
_cell_angle_alpha                84.236(3)
_cell_angle_beta                 83.690(4)
_cell_angle_gamma                64.991(6)
_cell_formula_units_Z            4
_cell_length_a                   11.7913(8)
_cell_length_b                   12.8318(8)
_cell_length_c                   14.3130(4)
_cell_measurement_reflns_used    6682
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      27.3990
_cell_measurement_theta_min      2.9140
_cell_volume                     1947.2(2)
_computing_cell_refinement       'CrysAlisPro, Rigaku OD'
_computing_data_collection       'CrysAlisPro, Rigaku OD'
_computing_data_reduction        'CrysAlisPro, Rigaku OD'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'CIFTAB-2014 (Sheldrick, 2014)'
_computing_structure_refinement  'SHELXL-2014/7 (Sheldrick, 2014)'
_computing_structure_solution    'SHELXS-2014 (Sheldrick, 2014)'
_diffrn_ambient_temperature      173(2)
_diffrn_detector_area_resol_mean 16.0382
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.888
_diffrn_measurement_device_type  'Agilent Xcalibur 3 E'
_diffrn_measurement_method       'omega scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0380
_diffrn_reflns_av_unetI/netI     0.0899
_diffrn_reflns_Laue_measured_fraction_full 0.999
_diffrn_reflns_Laue_measured_fraction_max 0.888
_diffrn_reflns_limit_h_max       15
_diffrn_reflns_limit_h_min       -15
_diffrn_reflns_limit_k_max       16
_diffrn_reflns_limit_k_min       -16
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       -18
_diffrn_reflns_number            12674
_diffrn_reflns_point_group_measured_fraction_full 0.999
_diffrn_reflns_point_group_measured_fraction_max 0.888
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         28.256
_diffrn_reflns_theta_min         2.299
_diffrn_source                   'Enhance (Mo) X-ray Source'
_exptl_absorpt_coefficient_mu    2.134
_exptl_absorpt_correction_T_max  0.774
_exptl_absorpt_correction_T_min  0.483
_exptl_absorpt_correction_type   analytical
_exptl_absorpt_process_details
; 
CrysAlisPro 1.171.38.43 (Rigaku Oxford Diffraction, 2015) 
Analytical numeric absorption correction using a multifaceted crystal 
model based on expressions derived by R.C. Clark & J.S. Reid. 
(Clark, R. C. & Reid, J. S. (1995). Acta Cryst. A51, 887-897) 
Empirical absorption correction using spherical harmonics, 
implemented in SCALE3 ABSPACK scaling algorithm. 
;
_exptl_crystal_colour            Colourless
_exptl_crystal_density_diffrn    1.444
_exptl_crystal_description       tablets
_exptl_crystal_F_000             880
_exptl_crystal_size_max          0.62
_exptl_crystal_size_mid          0.42
_exptl_crystal_size_min          0.13
_refine_diff_density_max         0.595
_refine_diff_density_min         -0.501
_refine_diff_density_rms         0.068
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.853
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     482
_refine_ls_number_reflns         12674
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.853
_refine_ls_R_factor_all          0.0736
_refine_ls_R_factor_gt           0.0350
_refine_ls_shift/su_max          0.002
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0400P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0713
_refine_ls_wR_factor_ref         0.0760
_reflns_Friedel_coverage         0.000
_reflns_number_gt                7571
_reflns_number_total             12674
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            jo8b02095_si_004.cif
_cod_data_source_block           42
_cod_database_code               4035746
_shelx_shelxl_version_number     2014/7
_shelx_res_checksum              83928
_shelx_hkl_checksum              4221