Regio- and Stereoselective Enolizations Using Calcium Bis(hexamethyldisilazide) as a Base: Synthetic, Solid-State, and Solution Studies
He, Xuyang; Hurley, Erin; Noll, Bruce C.; Henderson, Kenneth W.; Organometallics 27 (2008) 3094–; doi:10.1021/om7011908

data_4070988
_publ_section_title
;
 Regio- and Stereoselective Enolizations Using Calcium
 Bis(hexamethyldisilazide) as a Base: Synthetic, Solid-State, and Solution
 Studies
;
_journal_issue                   13
_journal_name_full               Organometallics
_journal_page_first              3094
_journal_paper_doi               10.1021/om7011908
_journal_volume                  27
_journal_year                    2008
_chemical_compound_source        synthesized
_chemical_formula_moiety         'C33 H55 Ca N O4 Si2'
_chemical_formula_sum            'C33 H55 Ca N O4 Si2'
_chemical_formula_weight         626.04
_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                 98.502(2)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   8.5176(3)
_cell_length_b                   19.9843(7)
_cell_length_c                   10.2846(4)
_cell_measurement_reflns_used    7668
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      30.6407
_cell_measurement_theta_min      2.2467
_cell_volume                     1731.39(11)
_computing_cell_refinement       'APEX2/SAINT (Bruker, 2004)'
_computing_data_collection       'APEX2 (Bruker, 2004)'
_computing_data_reduction        'SAINT/XPREP (Bruker, 2004; Sheldrick, 2003)'
_computing_molecular_graphics    'XP (Sheldrick, 1998)'
_computing_publication_material  'XCIF (Sheldrick, 2001)/enCIFer (CCDC, 2004)'
_computing_structure_refinement  'XL (Sheldrick, 2001)'
_computing_structure_solution    'XS (Sheldrick, 2001)'
_diffrn_ambient_temperature      100(2)
_diffrn_detector_area_resol_mean 8.33
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type  'Bruker X8-ApexII CCD diffractometer'
_diffrn_measurement_method       '\f and \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  0.0318
_diffrn_reflns_av_sigmaI/netI    0.0294
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       28
_diffrn_reflns_limit_k_min       -28
_diffrn_reflns_limit_l_max       14
_diffrn_reflns_limit_l_min       -14
_diffrn_reflns_number            46863
_diffrn_reflns_theta_full        30.51
_diffrn_reflns_theta_max         30.51
_diffrn_reflns_theta_min         2.00
_diffrn_source                   'fine-focus sealed tube'
_diffrn_source_type              'Siemens KFFMO2K-90'
_exptl_absorpt_coefficient_mu    0.286
_exptl_absorpt_correction_T_max  0.95
_exptl_absorpt_correction_T_min  0.93
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
Sheldrick, G. M. (2004). SADABS. University of G\"ottingen, Germany.
;
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.201
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             680
_exptl_crystal_recrystallization_method
'recrystallized from THF and hexane on cooling to 263 K'
_exptl_crystal_size_max          0.24
_exptl_crystal_size_mid          0.19
_exptl_crystal_size_min          0.18
_refine_diff_density_max         0.351
_refine_diff_density_min         -0.197
_refine_diff_density_rms         0.042
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -0.001(14)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.039
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     377
_refine_ls_number_reflns         10281
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.039
_refine_ls_R_factor_all          0.0297
_refine_ls_R_factor_gt           0.0274
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0423P)^2^+0.0598P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0674
_refine_ls_wR_factor_ref         0.0686
_reflns_number_gt                9783
_reflns_number_total             10281
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            om7011908-file001.cif
_cod_data_source_block           compound13
_cod_original_sg_symbol_H-M      'P 21'
_cod_database_code               4070988