A Practical Synthesis of 3-Acyl Cyclobutanones by [2 + 2] Annulation. Mechanism and Utility of the Zn(II)-Catalyzed Condensation of α-Chloroenamines with Electron-Deficient Alkenes
Jeannette M. O'Brien; Jason S. Kingsbury; Journal of Organic Chemistry 76 (2011) 1662–1672; doi:10.1021/jo102257k

data_4026107
_publ_section_title
;
 A Practical Synthesis of 3-Acyl Cyclobutanones by [2 + 2] Annulation.
 Mechanism and Utility of the Zn(II)-Catalyzed Condensation of
 \a-Chloroenamines with Electron-Deficient Alkenes
;
_journal_name_full               'Journal of Organic Chemistry'
_journal_page_first              1662
_journal_page_last               1672
_journal_paper_doi               10.1021/jo102257k
_journal_volume                  76
_journal_year                    2011
_chemical_absolute_configuration unk
_chemical_formula_moiety         'C15 H20 O2'
_chemical_formula_sum            'C15 H20 O2'
_chemical_formula_weight         232.31
_space_group_IT_number           19
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2ac 2ab'
_symmetry_space_group_name_H-M   'P 21 21 21'
_atom_sites_solution_hydrogens   difmap
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   6.2191(8)
_cell_length_b                   11.1721(14)
_cell_length_c                   17.860(2)
_cell_measurement_reflns_used    5309
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      28.19
_cell_measurement_theta_min      2.28
_cell_volume                     1240.9(3)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'Bruker SMART APEX CCD'
_diffrn_measurement_method       '0.3 deg wide \w exposures'
_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  0.0475
_diffrn_reflns_av_sigmaI/netI    0.0365
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       22
_diffrn_reflns_limit_l_min       -22
_diffrn_reflns_number            12713
_diffrn_reflns_theta_full        25.99
_diffrn_reflns_theta_max         25.99
_diffrn_reflns_theta_min         2.15
_exptl_absorpt_coefficient_mu    0.081
_exptl_absorpt_correction_T_max  0.9984
_exptl_absorpt_correction_T_min  0.9904
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   SADABS
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.243
_exptl_crystal_density_method    none
_exptl_crystal_description       plate
_exptl_crystal_F_000             504
_exptl_crystal_size_max          0.12
_exptl_crystal_size_mid          0.10
_exptl_crystal_size_min          0.02
_refine_diff_density_max         0.190
_refine_diff_density_min         -0.146
_refine_diff_density_rms         0.034
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.6(13)
_refine_ls_extinction_coef       na
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.032
_refine_ls_hydrogen_treatment    refxyz
_refine_ls_matrix_type           full
_refine_ls_number_parameters     214
_refine_ls_number_reflns         2437
_refine_ls_number_restraints     193
_refine_ls_restrained_S_all      0.994
_refine_ls_R_factor_all          0.0485
_refine_ls_R_factor_gt           0.0371
_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^)+(0.0398P)^2^+0.1562P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0769
_refine_ls_wR_factor_ref         0.0817
_reflns_number_gt                2107
_reflns_number_total             2437
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            jo102257k_si_002.cif
_cod_data_source_block           C15H20O2
_cod_database_code               4026107