Stereoselective construction of an unprecedented 7-8 fused ring system in micrandilactone a by [3,3]-sigmatropic rearrangement.
Zhang, Yan-Dong; Ren, Wei-Wu; Lan, Yu; Xiao, Qing; Wang, Kai; Xu, Jie; Chen, Jia-Hua; Yang, Zhen; Organic letters 10 (2008) 665–668; doi:10.1021/ol703126q

data_1504565
_publ_section_title
;
 Stereoselective construction of an unprecedented 7-8 fused ring system in
 micrandilactone a by [3,3]-sigmatropic rearrangement.
;
_journal_issue                   4
_journal_name_full               'Organic letters'
_journal_page_first              665
_journal_page_last               668
_journal_paper_doi               10.1021/ol703126q
_journal_volume                  10
_journal_year                    2008
_chemical_formula_moiety         'C21 H25 Br O3'
_chemical_formula_sum            'C21 H25 Br O3'
_chemical_formula_weight         405.30
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_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
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 90.8760(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   7.23240(10)
_cell_length_b                   15.6790(2)
_cell_length_c                   16.8439(2)
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      27.55
_cell_measurement_theta_min      1.77
_cell_volume                     1909.82(4)
_computing_cell_refinement       'SCALE(Otwinowski & Minor,1996)'
_computing_data_collection       'DENZO(Otwinowski & Minor,1996)'
_computing_data_reduction        'SCALE(Otwinowski & Minor,1996)'
_computing_molecular_graphics    'ORTEPII(Johnson,1976) and PLUTON(Spek,1990)'
_computing_publication_material  'SHELXL97(Sheldrick, 1997)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      296(2)
_diffrn_detector_area_resol_mean 0
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type  'MAC DIP 2030K'
_diffrn_measurement_method       \w
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'rotate anode'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0281
_diffrn_reflns_av_sigmaI/netI    0.0191
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       20
_diffrn_reflns_limit_k_min       -20
_diffrn_reflns_limit_l_max       21
_diffrn_reflns_limit_l_min       -21
_diffrn_reflns_number            28223
_diffrn_reflns_theta_full        27.55
_diffrn_reflns_theta_max         27.55
_diffrn_reflns_theta_min         1.77
_diffrn_standards_decay_%        0
_diffrn_standards_interval_count 0
_diffrn_standards_interval_time  0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    2.168
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.403
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             832
_exptl_crystal_size_max          0.20
_exptl_crystal_size_mid          0.20
_exptl_crystal_size_min          0.30
_refine_diff_density_max         0.363
_refine_diff_density_min         -0.510
_refine_diff_density_rms         0.052
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.022
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     226
_refine_ls_number_reflns         4403
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.022
_refine_ls_R_factor_all          0.0508
_refine_ls_R_factor_gt           0.0340
_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^)+(0.0404P)^2^+0.6728P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0811
_refine_ls_wR_factor_ref         0.0890
_reflns_number_gt                3357
_reflns_number_total             4403
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol703126q-file004.cif
_cod_data_source_block           a
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_database_code               1504565