Substrate-Controlled Diastereoselectivity Reversal in NHC-Catalyzed Cross-Benzoin Reactions Using N-Boc-N-Bn-Protected α-Amino Aldehydes.
Haghshenas, Pouyan; Quail, J. Wilson; Gravel, Michel; The Journal of organic chemistry 81 (2016) 12075–12083; doi:10.1021/acs.joc.6b02568

data_4037465
_publ_section_title
;
 Substrate-Controlled Diastereoselectivity Reversal in NHC-Catalyzed
 Cross-Benzoin Reactions Using N-Boc-N-Bn-Protected \a-Amino Aldehydes.
;
_journal_issue                   24
_journal_name_full               'The Journal of organic chemistry'
_journal_page_first              12075
_journal_page_last               12083
_journal_paper_doi               10.1021/acs.joc.6b02568
_journal_volume                  81
_journal_year                    2016
_chemical_absolute_configuration syn
_chemical_formula_moiety         'C20 H25 N O5'
_chemical_formula_sum            'C20 H25 N O5'
_chemical_formula_weight         359.41
_chemical_name_common            PH-5-110+98-A
_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'
_atom_sites_solution_hydrogens   mixed
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   10.1471(4)
_cell_length_b                   10.2402(4)
_cell_length_c                   18.2370(7)
_cell_measurement_reflns_used    9129
_cell_measurement_temperature    173.(2)
_cell_measurement_theta_max      28.2939
_cell_measurement_theta_min      2.8260
_cell_volume                     1894.98(13)
_computing_cell_refinement       'SAINT V8.34A (Bruker AXS Inc., 2013)'
_computing_data_collection       'Bruker Instrument Service v2013.12.0.0'
_computing_data_reduction        'SAINT V8.34A (Bruker AXS Inc., 2013)'
_computing_structure_refinement  'SHELXL-2014/6 (Sheldrick, 2014)'
_computing_structure_solution    'SHELXS-97 (Sheldrick 2008)'
_diffrn_ambient_temperature      173.(2)
_diffrn_detector_area_resol_mean 8.3333
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0236
_diffrn_reflns_av_sigmaI/netI    0.0137
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       23
_diffrn_reflns_limit_l_min       -24
_diffrn_reflns_number            35007
_diffrn_reflns_theta_full        28.30
_diffrn_reflns_theta_max         28.30
_diffrn_reflns_theta_min         2.99
_exptl_absorpt_coefficient_mu    0.090
_exptl_absorpt_correction_T_max  0.97
_exptl_absorpt_correction_T_min  0.90
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS V2014/2 (Bruker AXS Inc.)'
_exptl_crystal_colour            'clear colourless'
_exptl_crystal_density_diffrn    1.260
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       irregular
_exptl_crystal_F_000             768
_exptl_crystal_size_max          0.400
_exptl_crystal_size_mid          0.300
_exptl_crystal_size_min          0.300
_refine_diff_density_max         0.230
_refine_diff_density_min         -0.162
_refine_diff_density_rms         0.031
_refine_ls_abs_structure_details
;
Flack x determined using 1915 quotients [(I+)-(I-)]/[(I+)+(I-)]
(Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   -0.13(15)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.028
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     242
_refine_ls_number_reflns         4709
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.028
_refine_ls_R_factor_all          0.0308
_refine_ls_R_factor_gt           0.0291
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0449P)^2^+0.2226P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0753
_refine_ls_wR_factor_ref         0.0765
_reflns_number_gt                4507
_reflns_number_total             4709
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            jo6b02568_si_001.cif
_cod_data_source_block           I
_cod_database_code               4037465
_shelxl_version_number           2014/6
_shelx_res_checksum              4162
_shelx_hkl_checksum              70510