A chiral analog of the bicyclic guanidine TBD: synthesis, structure and Brønsted base catalysis.
Goldberg, Mariano; Sartakov, Denis; Bats, Jan W.; Bolte, Michael; Göbel, Michael W; Beilstein journal of organic chemistry 12 (2016) 1870–1876; doi:10.3762/bjoc.12.176

data_4032045
_publ_section_title
;
 A chiral analog of the bicyclic guanidine TBD: synthesis, structure and
 Br\/onsted base catalysis.
;
_journal_name_full               'Beilstein journal of organic chemistry'
_journal_page_first              1870
_journal_page_last               1876
_journal_paper_doi               10.3762/bjoc.12.176
_journal_volume                  12
_journal_year                    2016
_chemical_absolute_configuration ad
_chemical_formula_moiety         'C24 H16 Br N O3'
_chemical_formula_sum            'C24 H16 Br N O3'
_chemical_formula_weight         446.29
_space_group_crystal_system      orthorhombic
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_space_group_name_Hall           'P 2ac 2ab'
_space_group_name_H-M_alt        'P 21 21 21'
_symmetry_space_group_name_Hall  'P 2ac 2ab'
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_cell_length_c                   29.276(2)
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_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      24.4
_cell_measurement_theta_min      2.3
_cell_volume                     1899.3(3)
_computing_cell_refinement       'X-Area (Stoe & Cie, 2001)'
_computing_data_collection       'X-Area (Stoe & Cie, 2001)'
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_computing_molecular_graphics    'XP in SHELXTL-Plus (Sheldrick, 2008)'
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_diffrn_measurement_device_type  'STOE IPDS II two-circle-diffractometer'
_diffrn_measurement_method       \w
_diffrn_radiation_type           MoK\a
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_diffrn_reflns_av_R_equivalents  0.1359
_diffrn_reflns_av_unetI/netI     0.1834
_diffrn_reflns_Laue_measured_fraction_full 0.998
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_exptl_absorpt_correction_T_min  0.382
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_exptl_crystal_description       needle
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_refine_ls_abs_structure_details
; 
 Classical Flack method preferred over Parsons because s.u. lower. 
;
_refine_ls_abs_structure_Flack   -0.01(3)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.811
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
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_refine_ls_number_reflns         3341
_refine_ls_number_restraints     0
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_refine_ls_R_factor_all          0.1305
_refine_ls_R_factor_gt           0.0547
_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^)+(0.0116P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0886
_refine_ls_wR_factor_ref         0.1099
_reflns_Friedel_coverage         0.694
_reflns_Friedel_fraction_full    0.996
_reflns_Friedel_fraction_max     0.996
_reflns_number_gt                1667
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_reflns_threshold_expression     'I > 2\s(I)'
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_cod_data_source_block           g2
_cod_depositor_comments
'Adding full bibliography for 4032043--4032045.cif.'
_cod_database_code               4032045
_shelx_estimated_absorpt_t_min   0.600
_shelx_estimated_absorpt_t_max   0.978
_shelxl_version_number           2014/6
_shelx_res_checksum              32322
_shelx_hkl_checksum              8572