Organocatalytic Asymmetric Vinylogous α-Ketol Rearrangement: Enantioselective Construction of Chiral All-Carbon Quaternary Stereocenters in Spirocyclic Diketones via Semipinacol-Type 1,2-Carbon Migration
En Zhang; Chun-An Fan; Yong-Qiang Tu; Fu-Min Zhang; Yan-Lin Song; Journal of the American Chemical Society 131 (2009) 14626–14627; doi:10.1021/ja906291n

data_4105158
_publ_section_title
;
 Organocatalytic Asymmetric Vinylogous \a-Ketol Rearrangement:
 Enantioselective Construction of Chiral All-Carbon Quaternary
 Stereocenters in Spirocyclic Diketones via Semipinacol-Type 1,2-Carbon
 Migration
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              14626
_journal_page_last               14627
_journal_paper_doi               10.1021/ja906291n
_journal_volume                  131
_journal_year                    2009
_chemical_absolute_configuration none
_chemical_formula_sum            'C18 H21 Br O2'
_chemical_formula_weight         349.26
_space_group_IT_number           4
_symmetry_cell_setting           monoclinic
_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                 97.407(8)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   11.662(6)
_cell_length_b                   6.404(3)
_cell_length_c                   21.730(10)
_cell_measurement_reflns_used    1598
_cell_measurement_temperature    273(2)
_cell_measurement_theta_max      0.00
_cell_measurement_theta_min      0.00
_cell_volume                     1609.3(13)
_computing_cell_refinement       'Bruker SMART'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      273(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'CCD area detector'
_diffrn_measurement_method       'phi and omega scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0691
_diffrn_reflns_av_sigmaI/netI    0.1115
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -14
_diffrn_reflns_limit_k_max       6
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       27
_diffrn_reflns_limit_l_min       -27
_diffrn_reflns_number            9519
_diffrn_reflns_theta_full        27.00
_diffrn_reflns_theta_max         27.00
_diffrn_reflns_theta_min         1.76
_exptl_absorpt_coefficient_mu    2.556
_exptl_absorpt_correction_T_max  0.4891
_exptl_absorpt_correction_T_min  0.4042
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   SADABS
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.442
_exptl_crystal_description       block
_exptl_crystal_F_000             720
_exptl_crystal_size_max          0.37
_exptl_crystal_size_mid          0.32
_exptl_crystal_size_min          0.28
_refine_diff_density_max         0.450
_refine_diff_density_min         -0.423
_refine_diff_density_rms         0.061
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.003(11)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.976
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     383
_refine_ls_number_reflns         5486
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      0.976
_refine_ls_R_factor_all          0.1107
_refine_ls_R_factor_gt           0.0483
_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^)+(0.0020P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0922
_refine_ls_wR_factor_ref         0.1102
_reflns_number_gt                2914
_reflns_number_total             5486
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja906291n_si_003.cif
_cod_data_source_block           p21
_cod_database_code               4105158