Thermal C^2^-C^6^ Cyclization of Enyne-Allenes. Experimental Evidence for a Stepwise Mechanism and for an Unusual Thermal Silyl Shift
Michael Schmittel; Atul A. Mahajan; Götz Bucher; Jan W. Bats; Journal of Organic Chemistry 72 (2007) 2166–2173; doi:10.1021/jo062448+

data_4022798
_publ_section_title
;
 Thermal C^2^-C^6^ Cyclization of Enyne-Allenes. Experimental Evidence
 for a Stepwise Mechanism and for an Unusual Thermal Silyl Shift
;
_journal_name_full               'Journal of Organic Chemistry'
_journal_page_first              2166
_journal_page_last               2173
_journal_paper_doi               10.1021/jo062448+
_journal_volume                  72
_journal_year                    2007
_chemical_formula_moiety         'C53 H51 Br2 N Si'
_chemical_formula_sum            'C53 H51 Br2 N Si'
_chemical_formula_weight         889.86
_chemical_name_systematic
; 
 ? 
;
_space_group_IT_number           15
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-C 2yc'
_symmetry_space_group_name_H-M   'C 1 2/c 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                 110.669(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   27.611(6)
_cell_length_b                   10.9289(18)
_cell_length_c                   35.287(8)
_cell_measurement_reflns_used    100
_cell_measurement_temperature    183(2)
_cell_measurement_theta_max      23
_cell_measurement_theta_min      3
_cell_volume                     9963(3)
_computing_cell_refinement       'SMART (Siemens, 1995)'
_computing_data_collection       'SMART (Siemens, 1995)'
_computing_data_reduction        'SAINT (Siemens, 1995)'
_computing_publication_material  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      183(2)
_diffrn_measured_fraction_theta_full 0.997
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_device_type  SIEMENS_SMART_CCD
_diffrn_measurement_method       \w
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'normal-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.2510
_diffrn_reflns_av_sigmaI/netI    0.1799
_diffrn_reflns_limit_h_max       30
_diffrn_reflns_limit_h_min       -30
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       38
_diffrn_reflns_limit_l_min       -38
_diffrn_reflns_number            39505
_diffrn_reflns_theta_full        23.00
_diffrn_reflns_theta_max         23.00
_diffrn_reflns_theta_min         1.58
_diffrn_standards_decay_%        0.0
_diffrn_standards_interval_time  1200
_diffrn_standards_number         125
_exptl_absorpt_coefficient_mu    1.684
_exptl_absorpt_correction_T_max  0.772
_exptl_absorpt_correction_T_min  0.587
_exptl_absorpt_correction_type   numerical
_exptl_absorpt_process_details   ' SHELXTL (Sheldrick, 1996)'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.187
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             3680
_exptl_crystal_size_max          0.32
_exptl_crystal_size_mid          0.18
_exptl_crystal_size_min          0.18
_refine_diff_density_max         0.421
_refine_diff_density_min         -0.574
_refine_diff_density_rms         0.096
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.200
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     554
_refine_ls_number_reflns         6916
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.200
_refine_ls_R_factor_all          0.2023
_refine_ls_R_factor_gt           0.1131
_refine_ls_shift/su_max          0.093
_refine_ls_shift/su_mean         0.011
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.01P)^2^+90P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1772
_refine_ls_wR_factor_ref         0.2056
_reflns_number_gt                3498
_reflns_number_total             6934
_reflns_threshold_expression     I>2sigma(I)
_cod_data_source_file            jo062448+si20061129_012620.cif
_cod_data_source_block           compound_6c
_cod_original_sg_symbol_H-M      'C 2/c'
_cod_database_code               4022798