Enantioselective addition of nitromethane to 2-acylpyridine N-oxides. Expanding the generation of quaternary stereocenters with the Henry reaction.
Holmquist, Melireth; Blay, Gonzalo; Muñoz, M Carmen; Pedro, José R; Organic letters 16 (2014) 1204–1207; doi:10.1021/ol500082d

data_1513447
_publ_section_title
;
 Enantioselective addition of nitromethane to 2-acylpyridine N-oxides.
 Expanding the generation of quaternary stereocenters with the Henry
 reaction.
;
_journal_issue                   4
_journal_name_full               'Organic letters'
_journal_page_first              1204
_journal_page_last               1207
_journal_paper_doi               10.1021/ol500082d
_journal_volume                  16
_journal_year                    2014
_chemical_absolute_configuration ad
_chemical_formula_sum            'C16 H18 N2 O3'
_chemical_formula_weight         286.32
_space_group_IT_number           4
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  'P 2yb'
_symmetry_space_group_name_H-M   'P 1 21 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 110.4880(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   8.8910(3)
_cell_length_b                   9.4730(2)
_cell_length_c                   9.4720(3)
_cell_measurement_reflns_used    1801
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      27.485
_cell_measurement_theta_min      0.998
_cell_volume                     747.31(4)
_computing_cell_refinement       'HKL DENZO'
_computing_data_collection       COLLECT
_computing_data_reduction        'HKL DENZO and SCALEPACK'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    SHELXS-97
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.992
_diffrn_measured_fraction_theta_max 0.992
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0227
_diffrn_reflns_av_sigmaI/netI    0.0338
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -11
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       12
_diffrn_reflns_limit_l_min       -12
_diffrn_reflns_number            3351
_diffrn_reflns_theta_full        27.35
_diffrn_reflns_theta_max         27.35
_diffrn_reflns_theta_min         3.26
_exptl_absorpt_coefficient_mu    0.089
_exptl_absorpt_correction_T_max  0.9965
_exptl_absorpt_correction_T_min  0.9912
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details   'Empirical absorption correction:XABS2'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.272
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prismatic
_exptl_crystal_F_000             304
_exptl_crystal_size_max          0.10
_exptl_crystal_size_mid          0.04
_exptl_crystal_size_min          0.04
_refine_diff_density_max         0.146
_refine_diff_density_min         -0.146
_refine_diff_density_rms         0.036
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -0.5(17)
_refine_ls_extinction_coef       0.090(10)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   0.997
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     263
_refine_ls_number_reflns         3351
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      0.997
_refine_ls_R_factor_all          0.0910
_refine_ls_R_factor_gt           0.0486
_refine_ls_shift/su_max          0.005
_refine_ls_shift/su_mean         0.001
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0721P)^2^+0.1711P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1125
_refine_ls_wR_factor_ref         0.1465
_reflns_number_gt                2205
_reflns_number_total             3351
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol500082d_si_002.cif
_cod_data_source_block           shelxl
_cod_original_sg_symbol_H-M      P21
_cod_database_code               1513447