Modified chiral triazolium salts for enantioselective benzoin cyclization of enolizable keto-aldehydes: synthesis of (+)-sappanone B.
Takikawa, Hiroshi; Suzuki, Keisuke; Organic letters 9 (2007) 2713–2716; doi:10.1021/ol070929p

data_1505432
_publ_section_title
;
 Modified chiral triazolium salts for enantioselective benzoin cyclization
 of enolizable keto-aldehydes: synthesis of (+)-sappanone B.
;
_journal_issue                   14
_journal_name_full               'Organic letters'
_journal_page_first              2713
_journal_page_last               2716
_journal_paper_doi               10.1021/ol070929p
_journal_volume                  9
_journal_year                    2007
_chemical_absolute_configuration rm
_chemical_formula_moiety         'C20 H22 O6'
_chemical_formula_sum            'C20 H22 O6'
_chemical_formula_weight         358.38
_space_group_IT_number           5
_symmetry_cell_setting           monoclinic
_symmetry_Int_Tables_number      5
_symmetry_space_group_name_Hall  'C 2y'
_symmetry_space_group_name_H-M   'C 1 2 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                 114.247(4)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   26.729(3)
_cell_length_b                   6.1676(8)
_cell_length_c                   11.6348(14)
_cell_measurement_reflns_used    4118
_cell_measurement_temperature    173(2)
_cell_volume                     1748.8(4)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'ORTEP-3 for Windows (Farrugia, 1998)'
_computing_publication_material  SHELXL-97
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      173(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.938
_diffrn_measurement_device_type  'Bruker SMART CCD area detector system'
_diffrn_measurement_method       '\w scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0740
_diffrn_reflns_av_sigmaI/netI    0.0584
_diffrn_reflns_limit_h_max       29
_diffrn_reflns_limit_h_min       -40
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       17
_diffrn_reflns_limit_l_min       -15
_diffrn_reflns_number            9851
_diffrn_reflns_theta_full        27.50
_diffrn_reflns_theta_max         32.93
_diffrn_reflns_theta_min         1.67
_diffrn_source                   'rotating-anode X-ray tube'
_diffrn_source_type              'Rigaku Ultrax18'
_exptl_absorpt_coefficient_mu    0.100
_exptl_absorpt_correction_T_max  0.9960
_exptl_absorpt_correction_T_min  0.9515
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details   'absorption was corrected by SADABS'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.361
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             760
_exptl_crystal_size_max          0.50
_exptl_crystal_size_mid          0.30
_exptl_crystal_size_min          0.04
_refine_diff_density_max         0.296
_refine_diff_density_min         -0.254
_refine_diff_density_rms         0.059
_refine_ls_extinction_coef       0.0062(11)
_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   0.986
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     240
_refine_ls_number_reflns         3319
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      0.986
_refine_ls_R_factor_all          0.0583
_refine_ls_R_factor_gt           0.0428
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0608P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0998
_refine_ls_wR_factor_ref         0.1075
_reflns_number_gt                2717
_reflns_number_total             3319
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol070929psi20070420_023625.cif
_cod_data_source_block           15-camphanyl
_cod_original_sg_symbol_H-M      'C 2'
_cod_database_code               1505432