Highly enantioselective [4 + 2] cycloaddition reactions catalyzed by a chiral N-methyl-oxazaborolidinium cation.
Canales, Eda; Corey, E. J.; Organic letters 10 (2008) 3271–3273; doi:10.1021/ol8011502

data_1504781
_publ_section_title
;
 Highly enantioselective [4 + 2] cycloaddition reactions catalyzed by a
 chiral N-methyl-oxazaborolidinium cation.
;
_journal_issue                   15
_journal_name_full               'Organic letters'
_journal_page_first              3271
_journal_page_last               3273
_journal_paper_doi               10.1021/ol8011502
_journal_volume                  10
_journal_year                    2008
_chemical_absolute_configuration ad
_chemical_compound_source        'chemical synthesis'
_chemical_formula_iupac          'C24 H32 O3 Si'
_chemical_formula_moiety         'C24 H32 O3 Si'
_chemical_formula_structural     'C24 H32 O3 Si'
_chemical_formula_sum            'C24 H32 O3 Si'
_chemical_formula_weight         396.59
_chemical_melting_point          406.6(15)
_chemical_name_systematic
; 
(6aR,12aS,12bR)-5-(tert-Butyldimethylsilyloxy)-1,2,3,4,6,6a-
hexahydrotetraphene-7,12(12aH,12bH)-dione
;
_space_group_IT_number           4
_symmetry_cell_setting           monoclinic
_symmetry_Int_Tables_number      4
_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                 94.007(2)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   10.8960(3)
_cell_length_b                   8.1258(2)
_cell_length_c                   25.6367(8)
_cell_measurement_reflns_used    12699
_cell_measurement_temperature    193(2)
_cell_measurement_theta_max      27.22
_cell_measurement_theta_min      2.37
_cell_volume                     2264.29(11)
_computing_cell_refinement       'SAINT V7.34A (Bruker AXS, 2006b)'
_computing_data_collection       'APEX2 v2.1-0 (Bruker AXS, 2006a)'
_computing_data_reduction        'SAINT V7.34A (Bruker AXS, 2006b)'
_computing_molecular_graphics    'SHELXTL v6.12 (Bruker AXS, 2001)'
_computing_publication_material  'SHELXTL v6.12 (Bruker AXS, 2001)'
_computing_structure_refinement  'SHELXTL v6.12 (Bruker AXS, 2001)'
_computing_structure_solution    'SHELXTL v6.12 (Bruker AXS, 2001)'
_diffrn_ambient_temperature      193(2)
_diffrn_detector_area_resol_mean 836.6
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'Bruker APEX II CCD'
_diffrn_measurement_method       '\w scans, 1389 0.5\% rotations'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0444
_diffrn_reflns_av_sigmaI/netI    0.0405
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -14
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       33
_diffrn_reflns_limit_l_min       -33
_diffrn_reflns_number            36212
_diffrn_reflns_theta_full        27.50
_diffrn_reflns_theta_max         27.50
_diffrn_reflns_theta_min         1.87
_diffrn_standards_decay_%        0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.124
_exptl_absorpt_correction_T_max  0.9938
_exptl_absorpt_correction_T_min  0.9348
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS (Bruker AXS, 2004)'
_exptl_crystal_colour            Colorless
_exptl_crystal_density_diffrn    1.163
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       Plate
_exptl_crystal_F_000             856
_exptl_crystal_size_max          0.550
_exptl_crystal_size_mid          0.375
_exptl_crystal_size_min          0.050
_refine_diff_density_max         0.220
_refine_diff_density_min         -0.190
_refine_diff_density_rms         0.030
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -0.10(8)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.017
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     575
_refine_ls_number_reflns         10415
_refine_ls_number_restraints     151
_refine_ls_restrained_S_all      1.014
_refine_ls_R_factor_all          0.0470
_refine_ls_R_factor_gt           0.0372
_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^)+(0.0391P)^2^+0.3199P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0865
_refine_ls_wR_factor_ref         0.0921
_reflns_number_gt                9026
_reflns_number_total             10415
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            ol8011502-file003.cif
_cod_data_source_block           ejc150
_cod_depositor_comments
;
The following automatic conversions were performed:

'_chemical_melting_point' value '132-135\%C' was changed to
'406.6(15)' - it was converted from degrees Celsius(C) to Kelvins(K),
the average value was taken and precision was
estimated.

'_symmetry_cell_setting' value 'Monoclinic' changed to
'monoclinic' according to
/home/saulius/struct/CIF-dictionaries/cif_core.dic dictionary named
'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_values 1715 2011-07-08 13:25:40Z adriana 
;
_cod_original_sg_symbol_H-M      'P 21'
_cod_database_code               1504781