Origins of the Loss of Concertedness in Pericyclic Reactions: Theoretical Prediction and Direct Observation of Stepwise Mechanisms in [3 + 2] Thermal Cycloadditions
Silvia Vivanco; Begoña Lecea; Ana Arrieta; Pilar Prieto; Iñaki Morao; Anthony Linden; Fernando P. Cossío; Journal of the American Chemical Society 122 (2000) 6078–6092; doi:10.1021/ja9945360

data_4116055
_publ_contact_author_address
; Organisch-chemisches Institut
  Universit\"at Z\"urich
  Winterthurerstrasse 190
  CH-8057 Z\"urich
  Switzerland
;
_publ_contact_author_email       alinden@oci.unizh.ch
_publ_contact_author_fax         '41 1 635 6812'
_publ_contact_author_name        'Dr. Anthony Linden'
_publ_contact_author_phone       '41 1 635 4228'
_publ_section_title
;
 Origins of the Loss of Concertedness in Pericyclic Reactions: Theoretical
 Prediction and Direct Observation of Stepwise Mechanisms in [3 + 2]
 Thermal Cycloadditions
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              6078
_journal_page_last               6092
_journal_paper_doi               10.1021/ja9945360
_journal_volume                  122
_journal_year                    2000
_chemical_formula_moiety         'C14 H18 N2 O6 '
_chemical_formula_sum            'C14 H18 N2 O6'
_chemical_formula_weight         310.30
_chemical_melting_point          419(1)
_chemical_name_systematic
' (2S*,3R*)-Methyl 2-acetamido-3-(4-methoxyphenyl)-4-nitrobutyrate'
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_Int_Tables_number      14
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_cell_angle_alpha                90.0
_cell_angle_beta                 111.58(1)
_cell_angle_gamma                90.0
_cell_formula_units_Z            4
_cell_length_a                   10.600(1)
_cell_length_b                   15.514(2)
_cell_length_c                   10.014(2)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    173(1)
_cell_measurement_theta_max      18.5
_cell_measurement_theta_min      10.5
_cell_volume                     1531.4(4)
_computing_cell_refinement       'MSC/AFC Diffractometer Control Software'
_computing_data_collection
;
MSC/AFC Diffractometer Control Software (Molecular Structure
Corporation, 1991)
;
_computing_data_reduction
'teXsan (Molecular Structure Corporation, 1999)'
_computing_molecular_graphics    'ORTEPII (Johnson, 1976)'
_computing_publication_material  'TEXCIF (Linden, 1999)'
_computing_structure_refinement  teXsan
_computing_structure_solution    'SHELXS97 direct methods (Sheldrick, 1997)'
_diffrn_ambient_temperature      173(1)
_diffrn_detector                 'scintillation counter'
_diffrn_measured_fraction_theta_full 27.5
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Rigaku AFC5R diffractometer'
_diffrn_measurement_method       '\w--2\q scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'Rigaku RU200 rotating anode generator'
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71069
_diffrn_reflns_av_R_equivalents  0.049
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       0
_diffrn_reflns_limit_k_min       -20
_diffrn_reflns_limit_l_max       13
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            3838
_diffrn_reflns_theta_full        0.999
_diffrn_reflns_theta_max         27.5
_diffrn_reflns_theta_min         2.5
_diffrn_standards_decay_%        0
_diffrn_standards_interval_count 150
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    0.106
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.346
_exptl_crystal_description       plate
_exptl_crystal_F_000             656
_exptl_crystal_size_max          0.45
_exptl_crystal_size_mid          0.32
_exptl_crystal_size_min          0.14
_refine_diff_density_max         0.24
_refine_diff_density_min         -0.23
_refine_ls_abs_structure_details ' ?'
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_all   1.392
_refine_ls_goodness_of_fit_ref   1.686
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_constraints    0
_refine_ls_number_parameters     203
_refine_ls_number_reflns         1806
_refine_ls_number_restraints     0
_refine_ls_R_factor_all          0.1642
_refine_ls_R_factor_gt           0.0589
_refine_ls_shift/su_max          0.0001
_refine_ls_shift/su_mean         0.0000
_refine_ls_structure_factor_coef F
_refine_ls_weighting_details     '1/[^2^(F~o~) + (0.005F~o~)^2^]'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_all         0.0549
_refine_ls_wR_factor_gt          0.0463
_refine_ls_wR_factor_ref         0.0463
_reflns_number_gt                1806
_reflns_number_total             3506
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            ja9945360_2.cif
_cod_data_source_block           5bc_(L0003)
_cod_original_cell_volume        1531.3(4)
_cod_original_formula_sum        'C14 H18 N2 O6 '
_cod_database_code               4116055