Oxidative Prins and Prins/Friedel-Crafts cyclizations for the stereoselective synthesis of dioxabicycles and hexahydro-1H-benzo[f]isochromenes via the benzylic C-H activation.
Subba Reddy, B. V.; Borkar, Prashant; Yadav, J. S.; Purushotham Reddy, P.; Kunwar, A. C.; Sridhar, B.; Grée, René; Organic & biomolecular chemistry 10 (2012) 1349–1358; doi:10.1039/c1ob06489d

data_7152144
_publ_section_title
;
 Oxidative Prins and Prins/Friedel-Crafts cyclizations for the
 stereoselective synthesis of dioxabicycles and
 hexahydro-1H-benzo[f]isochromenes via the benzylic C-H activation.
;
_journal_issue                   7
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              1349
_journal_page_last               1358
_journal_paper_doi               10.1039/c1ob06489d
_journal_volume                  10
_journal_year                    2012
_chemical_formula_moiety         'C20 H22 O2'
_chemical_formula_sum            'C20 H22 O2'
_chemical_formula_weight         294.38
_chemical_name_systematic
;(4R,4aR,10bS)-4-(4-methoxyphenyl)-2,4,4a,5,6,10b-hexahydro-1H-
benzo[f]isochromene
;
_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
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 100.778(4)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   18.554(4)
_cell_length_b                   6.2560(15)
_cell_length_c                   13.851(3)
_cell_measurement_reflns_used    2544
_cell_measurement_temperature    294(2)
_cell_measurement_theta_max      23.78
_cell_measurement_theta_min      2.23
_cell_volume                     1579.4(6)
_computing_cell_refinement       'SAINT (Bruker, 2001)'
_computing_data_collection       'SMART (Bruker, 2001)'
_computing_data_reduction        SAINT
_computing_molecular_graphics    'SHELXTL/PC (Sheldrick, 1990)'
_computing_publication_material  SHELXL97
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      294(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device       'Bruker SMART APEX CCD area-detector'
_diffrn_measurement_device_type  'CCD Area Detector'
_diffrn_measurement_method       '\w scan'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0371
_diffrn_reflns_av_sigmaI/netI    0.0390
_diffrn_reflns_limit_h_max       22
_diffrn_reflns_limit_h_min       -22
_diffrn_reflns_limit_k_max       7
_diffrn_reflns_limit_k_min       -7
_diffrn_reflns_limit_l_max       16
_diffrn_reflns_limit_l_min       -16
_diffrn_reflns_number            12095
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         25.00
_diffrn_reflns_theta_min         1.12
_diffrn_source                   'fine-focus sealed tube'
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.078
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.238
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             632
_exptl_crystal_size_max          0.22
_exptl_crystal_size_mid          0.17
_exptl_crystal_size_min          0.09
_refine_diff_density_max         0.136
_refine_diff_density_min         -0.122
_refine_diff_density_rms         0.027
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.120
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     200
_refine_ls_number_reflns         2784
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.120
_refine_ls_R_factor_all          0.0798
_refine_ls_R_factor_gt           0.0554
_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^)+(0.0393P)^2^+0.2762P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1105
_refine_ls_wR_factor_ref         0.1233
_reflns_number_gt                2030
_reflns_number_total             2784
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            c1ob06489d.txt
_cod_data_source_block           aj73
_cod_original_cell_volume        1579.4(7)
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_database_code               7152144