Ground-State Distortion in N-Acyl-tert-butyl-carbamates (Boc) and N-Acyl-tosylamides (Ts): Twisted Amides of Relevance to Amide N-C Cross-Coupling.
Szostak, Roman; Shi, Shicheng; Meng, Guangrong; Lalancette, Roger; Szostak, Michal; The Journal of organic chemistry 81 (2016) 8091–8094; doi:10.1021/acs.joc.6b01560

data_4037118
_publ_section_title
;
 Ground-State Distortion in N-Acyl-tert-butyl-carbamates (Boc) and
 N-Acyl-tosylamides (Ts): Twisted Amides of Relevance to Amide N-C
 Cross-Coupling.
;
_journal_issue                   17
_journal_name_full               'The Journal of organic chemistry'
_journal_page_first              8091
_journal_page_last               8094
_journal_paper_doi               10.1021/acs.joc.6b01560
_journal_volume                  81
_journal_year                    2016
_chemical_absolute_configuration syn
_chemical_formula_moiety         'C18 H19 N O3'
_chemical_formula_sum            'C18 H19 N O3'
_chemical_formula_weight         297.34
_space_group_crystal_system      orthorhombic
_space_group_IT_number           33
_space_group_name_Hall           'P 2c -2n'
_space_group_name_H-M_alt        'P n a 21'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-2014/7
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   18.3730(8)
_cell_length_b                   14.1963(6)
_cell_length_c                   6.1767(3)
_cell_measurement_reflns_used    7852
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      68.73
_cell_measurement_theta_min      3.94
_cell_volume                     1611.06(13)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX2'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-2014 (Sheldrick 2014)'
_computing_structure_solution    'SHELXS-97 (Sheldrick 2008)'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 0.985
_diffrn_measured_fraction_theta_max 0.973
_diffrn_measurement_device_type  'Bruker SMART CCD Apex-II area-detector'
_diffrn_measurement_method       '\f and \w'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0622
_diffrn_reflns_av_unetI/netI     0.0406
_diffrn_reflns_Laue_measured_fraction_full 0.985
_diffrn_reflns_Laue_measured_fraction_max 0.973
_diffrn_reflns_limit_h_max       20
_diffrn_reflns_limit_h_min       -21
_diffrn_reflns_limit_k_max       16
_diffrn_reflns_limit_k_min       -16
_diffrn_reflns_limit_l_max       7
_diffrn_reflns_limit_l_min       -6
_diffrn_reflns_number            14144
_diffrn_reflns_point_group_measured_fraction_full 0.971
_diffrn_reflns_point_group_measured_fraction_max 0.955
_diffrn_reflns_theta_full        67.679
_diffrn_reflns_theta_max         68.727
_diffrn_reflns_theta_min         3.935
_diffrn_source                   'fine-focus sealed tube'
_exptl_absorpt_coefficient_mu    0.674
_exptl_absorpt_correction_T_max  0.968
_exptl_absorpt_correction_T_min  0.678
_exptl_absorpt_correction_type   numerical
_exptl_absorpt_process_details   'SADABS (Sheldrick, 2008a)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.226
_exptl_crystal_description       needle
_exptl_crystal_F_000             632
_exptl_crystal_size_max          0.377
_exptl_crystal_size_mid          0.178
_exptl_crystal_size_min          0.109
_refine_diff_density_max         0.316
_refine_diff_density_min         -0.154
_refine_diff_density_rms         0.039
_refine_ls_abs_structure_details
;
 Flack x determined using 1122 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.24(14)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.046
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     202
_refine_ls_number_reflns         2857
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.046
_refine_ls_R_factor_all          0.0422
_refine_ls_R_factor_gt           0.0404
_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^)+(0.0492P)^2^+0.5211P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1012
_refine_ls_wR_factor_ref         0.1024
_reflns_Friedel_coverage         0.785
_reflns_Friedel_fraction_full    0.954
_reflns_Friedel_fraction_max     0.933
_reflns_number_gt                2720
_reflns_number_total             2857
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            jo6b01560_si_002.cif
_cod_data_source_block           MENG_a
_cod_database_code               4037118
_shelx_shelxl_version_number     2014/7
_shelx_estimated_absorpt_t_min   0.785
_shelx_estimated_absorpt_t_max   0.930
_exptl_absorpt_special_details
'crystal mounted on a Cryoloop using Paratone-N'
_shelx_res_checksum              85910
_shelx_hkl_checksum              29384