A straightforward entry to chiral carbocyclic nucleoside analogues via the enantioselective [3+2] cycloaddition of α-nucleobase substituted acrylates.
Xie, Ming-Sheng; Wang, Yong; Li, Jian-Ping; Du, Cong; Zhang, Yan-Yan; Hao, Er-Jun; Zhang, Yi-Ming; Qu, Gui-Rong; Guo, Hai-Ming; Chemical communications (Cambridge, England) 51 (2015) 12451–12454; doi:10.1039/c5cc04832j

data_7117564
_publ_section_title
;
 A straightforward entry to chiral carbocyclic nucleoside analogues via
 the enantioselective [3+2] cycloaddition of \a-nucleobase substituted
 acrylates.
;
_journal_issue                   62
_journal_name_full               'Chemical communications (Cambridge, England)'
_journal_page_first              12451
_journal_page_last               12454
_journal_paper_doi               10.1039/c5cc04832j
_journal_volume                  51
_journal_year                    2015
_chemical_absolute_configuration unk
_chemical_formula_moiety         'C19 H21 Cl N4 O6'
_chemical_formula_sum            'C19 H21 Cl N4 O6'
_chemical_formula_weight         436.85
_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
_audit_update_record
;
2015-06-08 deposited with the CCDC.
2015-06-26 downloaded from the CCDC.
;
_cell_angle_alpha                90.00
_cell_angle_beta                 105.91(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   9.960(2)
_cell_length_b                   8.9114(18)
_cell_length_c                   12.427(3)
_cell_measurement_reflns_used    2443
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      22.17
_cell_measurement_theta_min      3.07
_cell_volume                     1060.7(4)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX2'
_computing_data_reduction        'Bruker SAINT  A '
_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      296(2)
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w 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  0.0319
_diffrn_reflns_av_sigmaI/netI    0.0441
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -11
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       14
_diffrn_reflns_limit_l_min       -14
_diffrn_reflns_number            7221
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         25.00
_diffrn_reflns_theta_min         1.70
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.223
_exptl_absorpt_correction_T_max  0.9463
_exptl_absorpt_correction_T_min  0.9161
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   sadabs
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.368
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             456
_exptl_crystal_size_max          0.40
_exptl_crystal_size_mid          0.30
_exptl_crystal_size_min          0.25
_refine_diff_density_max         0.121
_refine_diff_density_min         -0.198
_refine_diff_density_rms         0.031
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -0.01(7)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.028
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     274
_refine_ls_number_reflns         3709
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.028
_refine_ls_R_factor_all          0.0488
_refine_ls_R_factor_gt           0.0366
_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^)+(0.0434P)^2^+0.0465P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0829
_refine_ls_wR_factor_ref         0.0907
_reflns_number_gt                3057
_reflns_number_total             3709
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c5cc04832j2.cif
_cod_data_source_block           t
_cod_original_sg_symbol_H-M      'P 21'
_cod_database_code               7117564