Histidine-Catalyzed Asymmetric Aldol Addition of Enolizable Aldehydes: Insights into its Mechanism
Ulf Scheffler; Rainer Mahrwald; Journal of Organic Chemistry 77 (2012) 2310–2330; doi:10.1021/jo202558f

data_4027030
_publ_section_title
;
 Histidine-Catalyzed Asymmetric Aldol Addition of Enolizable Aldehydes:
 Insights into its Mechanism
;
_journal_name_full               'Journal of Organic Chemistry'
_journal_page_first              2310
_journal_page_last               2330
_journal_paper_doi               10.1021/jo202558f
_journal_volume                  77
_journal_year                    2012
_chemical_absolute_configuration syn
_chemical_formula_moiety         'C8 H16 O4'
_chemical_formula_sum            'C8 H16 O4'
_chemical_formula_weight         176.21
_chemical_name_systematic
; 
 (3S, 4S, 5R)-3-Ethyl-5-(hydroxymethyl)-3-methyltetrahydrofuran-2,4-diol 
;
_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                 104.406(5)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   6.0355(4)
_cell_length_b                   8.5641(4)
_cell_length_c                   8.9483(6)
_cell_measurement_reflns_used    8797
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      29.48
_cell_measurement_theta_min      2.35
_cell_volume                     447.98(5)
_computing_cell_refinement       'STOE X-AREA'
_computing_data_collection       'STOE X-AREA'
_computing_data_reduction        XPREP
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      100(2)
_diffrn_detector                 'image plate (34 cm diameter)'
_diffrn_detector_area_resol_mean 6.67
_diffrn_detector_type            STOE
_diffrn_measured_fraction_theta_full 0.992
_diffrn_measured_fraction_theta_max 0.992
_diffrn_measurement_details      ' 289 frames, detector distance = 100 mm'
_diffrn_measurement_device       '2-circle goniometer'
_diffrn_measurement_device_type  'STOE IPDS 2T'
_diffrn_measurement_method       'rotation method'
_diffrn_radiation_collimation    '0.5 mm diameter, monocapillary'
_diffrn_radiation_monochromator  'plane graphite'
_diffrn_radiation_polarisn_norm  0
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0382
_diffrn_reflns_av_unetI/netI     0.0528
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       11
_diffrn_reflns_limit_k_min       -11
_diffrn_reflns_limit_l_max       12
_diffrn_reflns_limit_l_min       -12
_diffrn_reflns_number            6755
_diffrn_reflns_theta_full        29.22
_diffrn_reflns_theta_max         29.22
_diffrn_reflns_theta_min         2.35
_diffrn_source
'sealed x-ray tube, 12 x 0.4 mm long-fine focus'
_diffrn_source_current           45
_diffrn_source_power             2.25
_diffrn_source_voltage           50
_exptl_absorpt_coefficient_mu    0.104
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.306
_exptl_crystal_description       fragment
_exptl_crystal_F_000             192
_exptl_crystal_size_max          0.20
_exptl_crystal_size_mid          0.12
_exptl_crystal_size_min          0.08
_refine_diff_density_max         0.151
_refine_diff_density_min         -0.188
_refine_diff_density_rms         0.034
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.859
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     114
_refine_ls_number_reflns         2323
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      0.859
_refine_ls_R_factor_all          0.0358
_refine_ls_R_factor_gt           0.0275
_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^)+(0.0275P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0519
_refine_ls_wR_factor_ref         0.0532
_reflns_d_resolution_high        0.728
_reflns_d_resolution_low         8.667
_reflns_limit_h_max              7
_reflns_limit_h_min              -8
_reflns_limit_k_max              11
_reflns_limit_k_min              -11
_reflns_limit_l_max              12
_reflns_limit_l_min              0
_reflns_number_gt                1133
_reflns_number_total             1284
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            jo202558f_23s34a29.cif
_cod_data_source_block           c:scheff23
_cod_original_sg_symbol_H-M      'P 21'
_cod_database_code               4027030