Approach to Merosesquiterpenes via Lewis Acid Catalyzed Nazarov-Type Cyclization: Total Synthesis of Akaol A.
Kakde, Badrinath N.; Kumar, Nivesh; Mondal, Pradip Kumar; Bisai, Alakesh; Organic letters 18 (2016) 1752–1755; doi:10.1021/acs.orglett.6b00446

data_1555507
_publ_section_title
;
 Approach to Merosesquiterpenes via Lewis Acid Catalyzed Nazarov-Type
 Cyclization: Total Synthesis of Akaol A.
;
_journal_issue                   8
_journal_name_full               'Organic letters'
_journal_page_first              1752
_journal_page_last               1755
_journal_paper_doi               10.1021/acs.orglett.6b00446
_journal_volume                  18
_journal_year                    2016
_chemical_absolute_configuration unk
_chemical_formula_sum            'C26 H38 O3'
_chemical_formula_weight         398.56
_space_group_crystal_system      monoclinic
_space_group_IT_number           4
_space_group_name_Hall           'P 2yb'
_space_group_name_H-M_alt        'P 1 21 1'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2014/7
_cell_angle_alpha                90
_cell_angle_beta                 96.9950(10)
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   10.3364(4)
_cell_length_b                   8.2959(3)
_cell_length_c                   12.9455(6)
_cell_measurement_reflns_used    2501
_cell_measurement_temperature    114(2)
_cell_measurement_theta_max      29.1
_cell_measurement_theta_min      2.5
_cell_volume                     1101.81(8)
_computing_structure_refinement  'SHELXL-2014/7 (Sheldrick, 2014)'
_diffrn_ambient_temperature      114(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.985
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0333
_diffrn_reflns_av_unetI/netI     0.0414
_diffrn_reflns_Laue_measured_fraction_full 0.999
_diffrn_reflns_Laue_measured_fraction_max 0.985
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -14
_diffrn_reflns_limit_k_max       11
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       -17
_diffrn_reflns_number            12627
_diffrn_reflns_point_group_measured_fraction_full 0.944
_diffrn_reflns_point_group_measured_fraction_max 0.867
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         30.034
_diffrn_reflns_theta_min         2.385
_exptl_absorpt_coefficient_mu    0.076
_exptl_absorpt_correction_T_max  0.9924
_exptl_absorpt_correction_T_min  0.9701
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   SABADS
_exptl_crystal_density_diffrn    1.201
_exptl_crystal_description       Plate
_exptl_crystal_F_000             436
_exptl_crystal_size_max          0.400
_exptl_crystal_size_mid          0.300
_exptl_crystal_size_min          0.100
_refine_diff_density_max         0.262
_refine_diff_density_min         -0.230
_refine_diff_density_rms         0.047
_refine_ls_abs_structure_details
;
 Flack x determined using 2028 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.033
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     269
_refine_ls_number_reflns         5601
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.033
_refine_ls_R_factor_all          0.0390
_refine_ls_R_factor_gt           0.0368
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0524P)^2^+0.1485P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0922
_refine_ls_wR_factor_ref         0.0938
_reflns_Friedel_coverage         0.655
_reflns_Friedel_fraction_full    0.880
_reflns_Friedel_fraction_max     0.734
_reflns_number_gt                5317
_reflns_number_total             5601
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            ol6b00446_si_003.cif
_cod_data_source_block           14th_H2
_cod_original_sg_symbol_H-M      'P 21'
_cod_database_code               1555507
_shelx_shelxl_version_number     2014/7
_shelx_estimated_absorpt_t_min   0.970
_shelx_estimated_absorpt_t_max   0.992
_shelx_res_checksum              82230
_shelx_hkl_checksum              90745