N-Heterocyclic Carbene Catalyzed Switchable Reactions of Enals with Azoalkenes: Formal [4 + 3] and [4 + 1] Annulations for the Synthesis of 1,2-Diazepines and Pyrazoles.
Guo, Chang; Sahoo, Basudev; Daniliuc, Constantin G.; Glorius, Frank; Journal of the American Chemical Society  (2014) 141203132036004–; doi:10.1021/ja510737n

data_4123023
_publ_section_title
;
 N-Heterocyclic Carbene Catalyzed Switchable Reactions of Enals with
 Azoalkenes: Formal [4 + 3] and [4 + 1] Annulations for the Synthesis of
 1,2-Diazepines and Pyrazoles.
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              141203132036004
_journal_paper_doi               10.1021/ja510737n
_journal_year                    2014
_chemical_absolute_configuration ad
_chemical_formula_sum            'C20 H22 N2 O4'
_chemical_formula_weight         354.39
_space_group_crystal_system      monoclinic
_space_group_IT_number           4
_space_group_name_Hall           'P 2yb'
_space_group_name_H-M_alt        'P 1 21 1'
_symmetry_space_group_name_Hall  'P 2yb'
_symmetry_space_group_name_H-M   'P 1 21 1'
_atom_sites_solution_hydrogens   geom
_cell_angle_alpha                90
_cell_angle_beta                 92.489(3)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   5.8916(3)
_cell_length_b                   11.8596(5)
_cell_length_c                   25.8111(11)
_cell_measurement_reflns_used    3286
_cell_measurement_temperature    100.(2)
_cell_measurement_theta_max      58.7606
_cell_measurement_theta_min      3.4279
_cell_volume                     1801.77(14)
_computing_cell_refinement       'SAINT V8.34A (Bruker AXS Inc., 2013)'
_computing_data_collection
;
APEX2 v.2014.1-1 (Bruker AXS Inc., 2014)
;
_computing_data_reduction        'SAINT V8.34A (Bruker AXS Inc., 2013)'
_computing_molecular_graphics    'XP (Sheldrick, 2014)'
_computing_publication_material  'SHELXL-2014 (Sheldrick, 2014)'
_computing_structure_refinement  'SHELXL-2014 (Sheldrick, 2014)'
_computing_structure_solution    'SHELXL-2014 (Sheldrick, 2014)'
_diffrn_ambient_temperature      100.(2)
_diffrn_detector_area_resol_mean 10.4167
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'Bruker D8 Venture PHOTON 100 CMOS'
_diffrn_measurement_method       'omega and phi scans'
_diffrn_radiation_monochromator  'MX mirror'
_diffrn_radiation_type           'Cu K\a'
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0871
_diffrn_reflns_av_unetI/netI     0.0844
_diffrn_reflns_limit_h_max       6
_diffrn_reflns_limit_h_min       -6
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       28
_diffrn_reflns_limit_l_min       -28
_diffrn_reflns_number            15935
_diffrn_reflns_theta_full        58.91
_diffrn_reflns_theta_max         58.91
_diffrn_reflns_theta_min         3.43
_diffrn_source                   'Cu ImS'
_diffrn_source_type              'micro focus tube'
_exptl_absorpt_coefficient_mu    0.749
_exptl_absorpt_correction_T_max  0.95
_exptl_absorpt_correction_T_min  0.81
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
Bruker AXS (2014). SADABS, Version 2014/2, Bruker AXS Inc., Madison, Wisconsin,
USA.
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.306
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             752
_exptl_crystal_size_max          0.191
_exptl_crystal_size_mid          0.178
_exptl_crystal_size_min          0.067
_refine_diff_density_max         0.331
_refine_diff_density_min         -0.207
_refine_ls_abs_structure_details
;
Flack x determined using 1550 quotients [(I+)-(I-)]/[(I+)+(I-)]
(Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.0(2)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.054
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     472
_refine_ls_number_reflns         5175
_refine_ls_number_restraints     25
_refine_ls_restrained_S_all      1.065
_refine_ls_R_factor_all          0.0762
_refine_ls_R_factor_gt           0.0542
_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^)+(0.0446P)^2^+0.3899P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1121
_refine_ls_wR_factor_ref         0.1222
_reflns_number_gt                4069
_reflns_number_total             5175
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            ja510737n_si_002.cif
_cod_data_source_block           glo7735
_cod_database_code               4123023