Conjugate-base-stabilized brønsted acids: catalytic enantioselective pictet-spengler reactions with unmodified tryptamine.
Mittal, Nisha; Sun, Diana X.; Seidel, Daniel; Organic letters 16 (2014) 1012–1015; doi:10.1021/ol403773a

data_1513490
_publ_section_title
;
 Conjugate-base-stabilized br\/onsted acids: catalytic enantioselective
 pictet-spengler reactions with unmodified tryptamine.
;
_journal_issue                   3
_journal_name_full               'Organic letters'
_journal_page_first              1012
_journal_page_last               1015
_journal_paper_doi               10.1021/ol403773a
_journal_volume                  16
_journal_year                    2014
_chemical_formula_sum            'C22 H23 Br N2 O2'
_chemical_formula_weight         427.33
_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'
_symmetry_space_group_name_Hall  'P 2ac 2ab'
_symmetry_space_group_name_H-M   'P 21 21 21'
_atom_sites_solution_hydrogens   geom
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_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   9.750(2)
_cell_length_b                   11.390(3)
_cell_length_c                   17.892(4)
_cell_measurement_reflns_used    1865
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      20.07
_cell_measurement_theta_min      2.28
_cell_volume                     1987.0(8)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX2'
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_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
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_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.1994
_diffrn_reflns_av_unetI/netI     0.1812
_diffrn_reflns_Laue_measured_fraction_full 0.533
_diffrn_reflns_Laue_measured_fraction_max 1.000
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -10
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_diffrn_reflns_limit_l_min       -17
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_diffrn_reflns_theta_min         2.120
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_exptl_absorpt_correction_T_max  0.4257
_exptl_absorpt_correction_T_min  0.2200
_exptl_absorpt_correction_type   multi-scan
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_exptl_crystal_F_000             880
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_refine_ls_abs_structure_details
; 
 Flack x determined using 307 quotients [(I+)-(I-)]/[(I+)+(I-)] 
 (Parsons and Flack (2004), Acta Cryst. A60, s61). 
;
_refine_ls_abs_structure_Flack   0.06(3)
_refine_ls_extinction_method     none
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_refine_ls_R_factor_all          0.1579
_refine_ls_R_factor_gt           0.0938
_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^)+(0.1000P)^2^+2.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1992
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_reflns_Friedel_coverage         0.693
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_reflns_number_gt                1111
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_cod_data_source_file            ol403773a_si_002.cif
_cod_data_source_block           nishabr_p212121
_cod_original_cell_volume        1987.2(7)
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_shelx_estimated_absorpt_t_min   0.546
_shelx_estimated_absorpt_t_max   0.990
_shelxl_version_number           2013-4
_shelx_res_checksum              34737
_shelx_hkl_checksum              98137