Cascade [1,3]-Sigmatropic Rearrangements of Ketene O,O-Acetals: Kinetic and DFT Level Mechanistic Studies
Perla Y. López-Camacho; Pedro Joseph-Nathan; Bárbara Gordillo-Román; Oscar R. Suárez-Castillo; Martha S. Morales-Ríos; Journal of Organic Chemistry 75 (2010) 1898–1910; doi:10.1021/jo902520z

data_4025299
_publ_section_title
;
 Cascade [1,3]-Sigmatropic Rearrangements of Ketene O,O-Acetals: Kinetic
 and DFT Level Mechanistic Studies
;
_journal_name_full               'Journal of Organic Chemistry'
_journal_page_first              1898
_journal_page_last               1910
_journal_paper_doi               10.1021/jo902520z
_journal_volume                  75
_journal_year                    2010
_chemical_formula_moiety         'C18 H20 N2 O4'
_chemical_formula_sum            'C18 H20 N2 O4'
_chemical_formula_weight         328.36
_chemical_name_systematic
;
Methyl 3-cyano-3a-tert-butyl-2-methoxy-3aH-furo[2,3-b]
indole-8(8aH)-carboxylate.
;
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2yn'
_symmetry_space_group_name_H-M   'P 1 21/n 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                 116.728(2)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   15.507(1)
_cell_length_b                   7.4079(5)
_cell_length_c                   16.512(1)
_cell_measurement_reflns_used    600
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      25
_cell_measurement_theta_min      2
_cell_volume                     1694.13(19)
_computing_cell_refinement       'Bruker Smart'
_computing_data_collection       'Bruker Smart'
_computing_data_reduction        'Bruker Smart'
_computing_molecular_graphics    'Ortep-3 for Windows (Farrugia, 1997)'
_computing_publication_material  'WinGX publication routines (Farrugia, 1999)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.996
_diffrn_measured_fraction_theta_max 0.996
_diffrn_measurement_device_type  'Bruker Smart 6000 CCD'
_diffrn_measurement_method       'Phi and omega 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  0.0511
_diffrn_reflns_av_sigmaI/netI    0.0573
_diffrn_reflns_limit_h_max       19
_diffrn_reflns_limit_h_min       -18
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       20
_diffrn_reflns_limit_l_min       -20
_diffrn_reflns_number            10903
_diffrn_reflns_theta_full        26.03
_diffrn_reflns_theta_max         26.03
_diffrn_reflns_theta_min         1.50
_diffrn_standards_decay_%        <1
_exptl_absorpt_coefficient_mu    0.092
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.287
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             696
_exptl_crystal_size_max          0.32
_exptl_crystal_size_mid          0.28
_exptl_crystal_size_min          0.25
_refine_diff_density_max         0.177
_refine_diff_density_min         -0.232
_refine_diff_density_rms         0.043
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.887
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     233
_refine_ls_number_reflns         3334
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.887
_refine_ls_R_factor_all          0.0825
_refine_ls_R_factor_gt           0.0430
_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^)+(0.0568P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0978
_refine_ls_wR_factor_ref         0.1109
_reflns_number_gt                1943
_reflns_number_total             3334
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            jo902520z_si_002_1.cif
_cod_data_source_block           2e
_cod_original_cell_volume        1694.08(19)
_cod_database_code               4025299