Tethered Tungsten-Alkylidenes for the Synthesis of Cyclic Polynorbornene via Ring Expansion Metathesis: Unprecedented Stereoselectivity and Trapping of Key Catalytic Intermediates.
Jakhar, Vineet; Pal, Digvijayee; Ghiviriga, Ion; Abboud, Khalil A.; Lester, Daniel W.; Sumerlin, Brent S.; Veige, Adam S.; Journal of the American Chemical Society 143 (2021) 1235–1246; doi:10.1021/jacs.0c12248

data_4135567
_publ_section_title
;
 Tethered Tungsten-Alkylidenes for the Synthesis of Cyclic Polynorbornene
 via Ring Expansion Metathesis: Unprecedented Stereoselectivity and
 Trapping of Key Catalytic Intermediates.
;
_journal_issue                   2
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              1235
_journal_page_last               1246
_journal_paper_doi               10.1021/jacs.0c12248
_journal_volume                  143
_journal_year                    2021
_chemical_formula_sum            'C40 H53 N O4 W'
_chemical_formula_weight         795.68
_space_group_crystal_system      monoclinic
_space_group_IT_number           14
_space_group_name_Hall           '-P 2ybc'
_space_group_name_H-M_alt        'P 1 21/c 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-2014/7
_cell_angle_alpha                90
_cell_angle_beta                 94.0853(6)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   11.4548(4)
_cell_length_b                   16.0612(5)
_cell_length_c                   19.5973(7)
_cell_measurement_reflns_used    9643
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      27.87
_cell_measurement_theta_min      2.19
_cell_volume                     3596.3(2)
_computing_cell_refinement       'Bruker APEX3 (Bruker, 2014)'
_computing_data_collection       'Bruker APEX3 (Bruker, 2014)'
_computing_data_reduction        'Bruker Apex3 SAINT (Bruker, 2014)'
_computing_molecular_graphics    'XP in SHELXTL-plus, Bruker 2014'
_computing_publication_material  'SHELXL2014/7, Sheldrick, G. M. 2014'
_computing_structure_refinement  'SHELXL2014/7, Sheldrick G. M. 2014'
_computing_structure_solution    'SHELXL2014/7, Sheldrick G. M. 2014'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'Bruker APEX-II DUO'
_diffrn_measurement_method       'phi and omega scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0230
_diffrn_reflns_av_unetI/netI     0.0105
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 1.000
_diffrn_reflns_limit_h_max       15
_diffrn_reflns_limit_h_min       -15
_diffrn_reflns_limit_k_max       21
_diffrn_reflns_limit_k_min       -20
_diffrn_reflns_limit_l_max       25
_diffrn_reflns_limit_l_min       -25
_diffrn_reflns_number            80798
_diffrn_reflns_point_group_measured_fraction_full 1.000
_diffrn_reflns_point_group_measured_fraction_max 1.000
_diffrn_reflns_theta_full        25.000
_diffrn_reflns_theta_max         27.878
_diffrn_reflns_theta_min         1.641
_diffrn_source                   'fine-focus sealed tube'
_exptl_absorpt_coefficient_mu    3.253
_exptl_absorpt_correction_T_max  0.8503
_exptl_absorpt_correction_T_min  0.6879
_exptl_absorpt_correction_type   integration
_exptl_absorpt_process_details
'based on measured indexed crystal faces, Bruker SHELXTL2014 (Sheldrick, 2014)'
_exptl_crystal_colour            yellow
_exptl_crystal_density_diffrn    1.470
_exptl_crystal_description       Plate
_exptl_crystal_F_000             1624
_exptl_crystal_size_max          0.130
_exptl_crystal_size_mid          0.109
_exptl_crystal_size_min          0.053
_exptl_transmission_factor_max   0.5631
_exptl_transmission_factor_min   0.4978
_refine_diff_density_max         0.555
_refine_diff_density_min         -0.328
_refine_diff_density_rms         0.054
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.034
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     427
_refine_ls_number_reflns         8572
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.034
_refine_ls_R_factor_all          0.0140
_refine_ls_R_factor_gt           0.0121
_refine_ls_shift/su_max          0.007
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0169P)^2^+1.6043P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0310
_refine_ls_wR_factor_ref         0.0315
_reflns_Friedel_coverage         0.000
_reflns_number_gt                7921
_reflns_number_total             8572
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            ja0c12248_si_004.cif
_cod_data_source_block           vj14
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_database_code               4135567
_shelx_shelxl_version_number     2014/7
_shelx_estimated_absorpt_t_min   0.677
_shelx_estimated_absorpt_t_max   0.847
_shelx_res_checksum              74439
_shelx_hkl_checksum              97610