Formal Intramolecular (4 + 1)-Cycloaddition of Dialkoxycarbenes: Control of the Stereoselectivity and a Mechanistic Portrait
Francis Beaumier; Marianne Dupuis; Claude Spino; Claude Y. Legault; Journal of the American Chemical Society 134 (2012) 5938–5953; doi:10.1021/ja211927b

data_4117755
_publ_section_title
;
 Formal Intramolecular (4 + 1)-Cycloaddition of Dialkoxycarbenes: Control
 of the Stereoselectivity and a Mechanistic Portrait
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              5938
_journal_page_last               5953
_journal_paper_doi               10.1021/ja211927b
_journal_volume                  134
_journal_year                    2012
_chemical_formula_sum            'C20 H25 Br O4'
_chemical_formula_weight         409.32
_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_conform_dict_location     ftp://ftp.iucr.org/pub/cif_core.dic
_audit_conform_dict_name         cif_core.dic
_audit_conform_dict_version      2.3
_audit_creation_date             2010-08-09T13:29:06-00:00
_audit_creation_method           'WinGX routine CIF_UPDATE'
_cell_angle_alpha                86.960(18)
_cell_angle_beta                 80.68(2)
_cell_angle_gamma                80.571(17)
_cell_formula_units_Z            2
_cell_length_a                   6.1743(18)
_cell_length_b                   12.3846(17)
_cell_length_c                   13.243(4)
_cell_measurement_reflns_used    20
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      35
_cell_measurement_theta_min      30
_cell_volume                     985.4(4)
_computing_cell_refinement       Difrac
_computing_data_collection       Difrac
_computing_data_reduction        NRCVAX
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.969
_diffrn_measured_fraction_theta_max 0.969
_diffrn_measurement_device_type  CAD4
_diffrn_measurement_method       Omega
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54176
_diffrn_reflns_av_R_equivalents  0
_diffrn_reflns_av_unetI/netI     0.1007
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       15
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       16
_diffrn_reflns_limit_l_min       -15
_diffrn_reflns_number            3598
_diffrn_reflns_theta_full        69.55
_diffrn_reflns_theta_max         69.55
_diffrn_reflns_theta_min         3.38
_diffrn_standards_decay_%        0
_diffrn_standards_interval_count 100
_diffrn_standards_number         1
_exptl_absorpt_coefficient_mu    3.01
_exptl_absorpt_correction_T_max  0.902
_exptl_absorpt_correction_T_min  0.634
_exptl_absorpt_correction_type   psi-scan
_exptl_absorpt_process_details   empirical
_exptl_crystal_colour            Colorless
_exptl_crystal_density_diffrn    1.379
_exptl_crystal_description       Needle
_exptl_crystal_F_000             424
_exptl_crystal_size_max          0.6
_exptl_crystal_size_mid          0.2
_exptl_crystal_size_min          0.05
_refine_diff_density_max         0.349
_refine_diff_density_min         -0.395
_refine_diff_density_rms         0.073
_refine_ls_extinction_coef       0.0076(12)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   0.872
_refine_ls_hydrogen_treatment    none
_refine_ls_matrix_type           full
_refine_ls_number_parameters     227
_refine_ls_number_reflns         3598
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.872
_refine_ls_R_factor_all          0.2242
_refine_ls_R_factor_gt           0.0841
_refine_ls_shift/su_max          0
_refine_ls_shift/su_mean         0
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.1223P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1986
_refine_ls_wR_factor_ref         0.2482
_reflns_number_gt                1227
_reflns_number_total             3598
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja211927b_si_010.cif
_cod_data_source_block           fb6028
_cod_depositor_comments
;
The following automatic conversions were performed:

'_exptl_absorpt_correction_type' value 'Psi-Scan' changed to
'psi-scan' according to the built-in table from CIF Core dictionary
named 'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_values 1715 2011-07-08 13:25:40Z adriana 
;
_cod_database_code               4117755