Synthesis of benzofurans via an acid catalysed transacetalisation/Fries-type O → C rearrangement/Michael addition/ring-opening aromatisation cascade of β-pyrones.
Bankar, Siddheshwar K.; Mathew, Jopaul; Ramasastry, S. S. V.; Chemical communications (Cambridge, England) 52 (2016) 5569–5572; doi:10.1039/c6cc01016d

data_7124590
_publ_section_title
;
 Synthesis of benzofurans via an acid catalysed
 transacetalisation/Fries-type O \\rightarrow C rearrangement/Michael
 addition/ring-opening aromatisation cascade of \b-pyrones.
;
_journal_issue                   32
_journal_name_full               'Chemical communications (Cambridge, England)'
_journal_page_first              5569
_journal_page_last               5572
_journal_paper_doi               10.1039/c6cc01016d
_journal_volume                  52
_journal_year                    2016
_chemical_formula_moiety         '2(C14 H15 Br O3)'
_chemical_formula_sum            'C28 H30 Br2 O6'
_chemical_formula_weight         622.35
_space_group_crystal_system      triclinic
_space_group_IT_number           2
_space_group_name_Hall           '-P 1'
_space_group_name_H-M_alt        'P -1'
_symmetry_Int_Tables_number      2
_audit_block_doi                 10.5517/cc1kcldx
_audit_creation_date             2015-12-08
_audit_creation_method
;
Olex2 1.2
(compiled 2015.09.30 svn.r3233 for OlexSys, GUI svn.r5103)
;
_audit_update_record
;
2015-12-08 deposited with the CCDC.
2016-03-17 downloaded from the CCDC.
;
_cell_angle_alpha                102.86(3)
_cell_angle_beta                 98.09(3)
_cell_angle_gamma                90.08(4)
_cell_formula_units_Z            2
_cell_length_a                   7.840(2)
_cell_length_b                   11.999(3)
_cell_length_c                   15.345(2)
_cell_volume                     1392.5(6)
_computing_molecular_graphics    'Olex2 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 (Dolomanov et al., 2009)'
_computing_structure_refinement  'olex2.refine (Bourhis et al., 2015)'
_computing_structure_solution    'olex2.solve (Bourhis et al., 2015)'
_diffrn_measured_fraction_theta_full 0.9643
_diffrn_measured_fraction_theta_max 0.9643
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71075
_diffrn_reflns_av_R_equivalents  0.0521
_diffrn_reflns_av_unetI/netI     0.0634
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       15
_diffrn_reflns_limit_k_min       -15
_diffrn_reflns_limit_l_max       19
_diffrn_reflns_limit_l_min       -19
_diffrn_reflns_number            14248
_diffrn_reflns_theta_full        27.6147
_diffrn_reflns_theta_max         27.61
_diffrn_reflns_theta_min         3.14
_exptl_absorpt_coefficient_mu    2.949
_exptl_crystal_density_diffrn    1.4841
_exptl_crystal_F_000             631.2026
_refine_diff_density_max         1.8191
_refine_diff_density_min         -1.2588
_refine_diff_density_rms         0.1728
_refine_ls_d_res_high            0.7667
_refine_ls_d_res_low             6.4955
_refine_ls_goodness_of_fit_ref   1.0101
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_constraints    46
_refine_ls_number_parameters     330
_refine_ls_number_reflns         6248
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.0101
_refine_ls_R_factor_all          0.1231
_refine_ls_R_factor_gt           0.0770
_refine_ls_shift/su_max          0.0000
_refine_ls_shift/su_mean         0.0000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.1205P)^2^+2.1670P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.2032
_refine_ls_wR_factor_ref         0.2399
_reflns_Friedel_coverage         0.0
_reflns_limit_h_max              9
_reflns_limit_h_min              -9
_reflns_limit_k_max              15
_reflns_limit_k_min              -15
_reflns_limit_l_max              19
_reflns_limit_l_min              0
_reflns_number_gt                3651
_reflns_number_total             6248
_reflns_threshold_expression     I>=2u(I)
_cod_data_source_file            c6cc01016d2.cif
_cod_data_source_block           shelx4
_cod_database_code               7124590
_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:
 C14(H14), C27(H27)
2.b Secondary CH2 refined with riding coordinates:
 C21(H21a,H21b), C30(H30a,H30b)
2.c Aromatic/amide H refined with riding coordinates:
 C12(H12), C38(H38), C22(H22), C19(H19), C29(H29), C20(H20)
2.d Idealised Me refined as rotating group:
 C25(H25a,H25b,H25c), C28(H28a,H28b,H28c), C31(H31a,H31b,H31c), C32(H32a,H32b,
 H32c), C34(H34a,H34b,H34c), C37(H37a,H37b,H37c)
;
_olex2_submission_special_instructions 'No special instructions were received'