Highly enantioenriched homoenolate reagents by asymmetric gamma-deprotonation of achiral 1-silyl-substituted 1-alkenyl carbamates.
Reuber, Jenny; Fröhlich, Roland; Hoppe, Dieter; Organic letters 6 (2004) 783–786; doi:10.1021/ol0364677

data_1506910
_publ_section_title
;
 Highly enantioenriched homoenolate reagents by asymmetric
 gamma-deprotonation of achiral 1-silyl-substituted 1-alkenyl carbamates.
;
_journal_issue                   5
_journal_name_full               'Organic letters'
_journal_page_first              783
_journal_page_last               786
_journal_paper_doi               10.1021/ol0364677
_journal_volume                  6
_journal_year                    2004
_chemical_formula_sum            'C22 H39 N O2 Si2'
_chemical_formula_weight         405.72
_space_group_IT_number           33
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2c -2n'
_symmetry_space_group_name_H-M   'P n a 21'
_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                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   21.838(1)
_cell_length_b                   9.844(2)
_cell_length_c                   12.235(1)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    223(2)
_cell_measurement_theta_max      46.91
_cell_measurement_theta_min      40.03
_cell_volume                     2630.2(6)
_computing_cell_refinement       'EXpress (Nonius B.V., 1994)'
_computing_data_collection       'Express (Nonius B.V., 1994)'
_computing_data_reduction        'MolEN (Fair, 1990)'
_computing_molecular_graphics    'Diamond (Brandenburg, 1997)'
_computing_publication_material  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      223(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'Enraf Nonius CAD4'
_diffrn_measurement_method       '\w/2\q scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0000
_diffrn_reflns_av_sigmaI/netI    0.0249
_diffrn_reflns_limit_h_max       0
_diffrn_reflns_limit_h_min       -27
_diffrn_reflns_limit_k_max       0
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       0
_diffrn_reflns_limit_l_min       -15
_diffrn_reflns_number            2810
_diffrn_reflns_theta_full        74.25
_diffrn_reflns_theta_max         74.25
_diffrn_reflns_theta_min         4.05
_diffrn_standards_decay_%        1.7
_diffrn_standards_interval_count 250
_diffrn_standards_interval_time  120
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    1.327
_exptl_absorpt_correction_T_max  0.7773
_exptl_absorpt_correction_T_min  0.6189
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details   'based on \y scan data'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.025
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             888
_exptl_crystal_size_max          0.40
_exptl_crystal_size_mid          0.25
_exptl_crystal_size_min          0.20
_refine_diff_density_max         0.272
_refine_diff_density_min         -0.265
_refine_diff_density_rms         0.051
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.01(5)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.035
_refine_ls_hydrogen_treatment    'refined as riding atoms'
_refine_ls_matrix_type           full
_refine_ls_number_parameters     254
_refine_ls_number_reflns         2810
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.035
_refine_ls_R_factor_all          0.0691
_refine_ls_R_factor_gt           0.0522
_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^)+(0.0972P)^2^+0.5349P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1398
_refine_ls_wR_factor_ref         0.1528
_reflns_number_gt                2370
_reflns_number_total             2810
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol0364677si20040127_124314.cif
_cod_data_source_block           hop2452
_cod_original_sg_symbol_H-M      Pna21
_cod_database_code               1506910