Intramolecular nitrone dipolar cycloadditions: control of regioselectivity and synthesis of naturally-occurring spirocyclic alkaloids.
Hodges, Alastair J.; Adams, Joseph P.; Bond, Andrew D.; Holmes, Andrew B.; Press, Neil J.; Roughley, Stephen D.; Ryan, John H.; Saubern, Simon; Smith, Catherine J.; Turnbull, Michael D.; Newton, Annabella F.; Organic & biomolecular chemistry 10 (2012) 8963–8974; doi:10.1039/c2ob26333e

data_7152687
_publ_section_title
;
 Intramolecular nitrone dipolar cycloadditions: control of
 regioselectivity and synthesis of naturally-occurring spirocyclic
 alkaloids.
;
_journal_issue                   45
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              8963
_journal_page_last               8974
_journal_paper_doi               10.1039/c2ob26333e
_journal_volume                  10
_journal_year                    2012
_chemical_formula_moiety         'C33 H44 N O2 Si +, Cl -'
_chemical_formula_sum            'C33 H44 Cl N O2 Si'
_chemical_formula_weight         550.23
_space_group_IT_number           2
_symmetry_cell_setting           triclinic
_symmetry_space_group_name_Hall  '-P 1'
_symmetry_space_group_name_H-M   'P -1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                84.294(3)
_cell_angle_beta                 75.250(4)
_cell_angle_gamma                89.894(4)
_cell_formula_units_Z            4
_cell_length_a                   11.7549(6)
_cell_length_b                   13.7175(9)
_cell_length_c                   20.1662(13)
_cell_measurement_reflns_used    240098
_cell_measurement_temperature    180(2)
_cell_measurement_theta_max      25.03
_cell_measurement_theta_min      1.00
_cell_volume                     3128.1(3)
_computing_cell_refinement       'HKL Scalepack (Otwinowski & Minor, 1997)'
_computing_data_collection       'Collect (Nonius, 1998)'
_computing_data_reduction
;
HKL Denzo and Scalepack (Otwinowski & Minor, 1997)
;
_computing_publication_material  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SIR-92 (Altomare et al., 1994)'
_diffrn_ambient_temperature      180(2)
_diffrn_measured_fraction_theta_full 0.978
_diffrn_measured_fraction_theta_max 0.978
_diffrn_measurement_device_type  'Nonius KappaCCD'
_diffrn_measurement_method       'Thin slice \w and \f 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  0.0510
_diffrn_reflns_av_sigmaI/netI    0.0605
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       16
_diffrn_reflns_limit_k_min       -16
_diffrn_reflns_limit_l_max       23
_diffrn_reflns_limit_l_min       -22
_diffrn_reflns_number            26871
_diffrn_reflns_theta_full        24.97
_diffrn_reflns_theta_max         24.97
_diffrn_reflns_theta_min         3.77
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.189
_exptl_absorpt_correction_T_max  0.998
_exptl_absorpt_correction_T_min  0.867
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'Sortav Blessing (1995)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.168
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             1184
_exptl_crystal_size_max          0.35
_exptl_crystal_size_mid          0.18
_exptl_crystal_size_min          0.05
_refine_diff_density_max         0.512
_refine_diff_density_min         -0.304
_refine_diff_density_rms         0.059
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.128
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     699
_refine_ls_number_reflns         10742
_refine_ls_number_restraints     2
_refine_ls_restrained_S_all      1.128
_refine_ls_R_factor_all          0.1063
_refine_ls_R_factor_gt           0.0729
_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^)+(0.0471P)^2^+5.4705P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1677
_refine_ls_wR_factor_ref         0.1828
_reflns_number_gt                7651
_reflns_number_total             10742
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            c2ob26333e.txt
_cod_data_source_block           ah0134
_cod_database_code               7152687