An efficient synthesis strategy to the core structure of 6-5-6-5-6-membered epipolythiodiketopiperazines.
Zipfel, Hannes F.; Carreira, Erick M.; Organic letters 16 (2014) 2854–2857; doi:10.1021/ol500990f

data_1516148
_publ_section_title
;
 An efficient synthesis strategy to the core structure of
 6-5-6-5-6-membered epipolythiodiketopiperazines.
;
_journal_issue                   11
_journal_name_full               'Organic letters'
_journal_page_first              2854
_journal_page_last               2857
_journal_paper_doi               10.1021/ol500990f
_journal_volume                  16
_journal_year                    2014
_chemical_absolute_configuration ad
_chemical_formula_moiety         'C21 H24 N2 O4 S'
_chemical_formula_sum            'C21 H24 N2 O4 S'
_chemical_formula_weight         400.48
_chemical_name_systematic
'(2R,3S)-ethyl 3-(1H-indol-3-yl)-2-(4-methylphenylsulfonamido)butanoate'
_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'
_symmetry_cell_setting           monoclinic
_symmetry_Int_Tables_number      4
_symmetry_space_group_name_Hall  'P 2yb'
_symmetry_space_group_name_H-M   'P 1 21 1'
_atom_sites_solution_hydrogens   mixed
_atom_sites_solution_primary     direct
_audit_creation_date             2013-12-16
_audit_creation_method
;
Olex2 1.2
(compiled 2013.12.10 svn.r2850 for OlexSys, GUI svn.r4736)
;
_cell_angle_alpha                90
_cell_angle_beta                 106.278(3)
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   11.6390(7)
_cell_length_b                   5.5765(3)
_cell_length_c                   15.5447(10)
_cell_measurement_reflns_used    5959
_cell_measurement_temperature    100
_cell_measurement_theta_max      27.53
_cell_measurement_theta_min      2.57
_cell_volume                     968.48(10)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX2'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    OLEX2
_computing_publication_material  OLEX2
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'XS (Sheldrick, 2008)'
_diffrn_ambient_temperature      100.0(2)
_diffrn_detector                 'Bruker APEX2 area detector'
_diffrn_detector_area_resol_mean 8.33
_diffrn_detector_type            'CCD area detector'
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device       'kappa-stage diffractometer'
_diffrn_measurement_device_type  'Bruker/Nonius Kappa Apex2'
_diffrn_measurement_method       '\w and \f scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0442
_diffrn_reflns_av_unetI/netI     0.0471
_diffrn_reflns_Laue_measured_fraction_full 0.998
_diffrn_reflns_Laue_measured_fraction_max 0.998
_diffrn_reflns_limit_h_max       15
_diffrn_reflns_limit_h_min       -15
_diffrn_reflns_limit_k_max       7
_diffrn_reflns_limit_k_min       -7
_diffrn_reflns_limit_l_max       20
_diffrn_reflns_limit_l_min       -20
_diffrn_reflns_number            22103
_diffrn_reflns_point_group_measured_fraction_full 0.999
_diffrn_reflns_point_group_measured_fraction_max 0.998
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         27.594
_diffrn_reflns_theta_min         2.565
_diffrn_source                   'sealed tube'
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.198
_exptl_absorpt_correction_T_max  0.7456
_exptl_absorpt_correction_T_min  0.6831
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
SADABS-2008/1 (Bruker,2008) was used for absorption correction.
wR2(int) was 0.0560 before and 0.0501 after correction.
The Ratio of minimum to maximum transmission is 0.9162.
The \l/2 correction factor is 0.0000.
;
_exptl_crystal_colour            'clear colourless'
_exptl_crystal_colour_lustre     clear
_exptl_crystal_colour_primary    colourless
_exptl_crystal_density_diffrn    1.373
_exptl_crystal_description       needle
_exptl_crystal_F_000             424
_exptl_crystal_recrystallization_method 'Crystallized form CDCl3'
_exptl_crystal_size_max          0.24
_exptl_crystal_size_mid          0.045
_exptl_crystal_size_min          0.015
_refine_diff_density_max         0.234
_refine_diff_density_min         -0.312
_refine_diff_density_rms         0.047
_refine_ls_abs_structure_details
;
 Flack x determined using 1555 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons and Flack (2004), Acta Cryst. A60, s61).
;
_refine_ls_abs_structure_Flack   0.04(3)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.028
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     262
_refine_ls_number_reflns         4487
_refine_ls_number_restraints     3
_refine_ls_restrained_S_all      1.029
_refine_ls_R_factor_all          0.0465
_refine_ls_R_factor_gt           0.0341
_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^)+(0.0365P)^2^+0.0450P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0678
_refine_ls_wR_factor_ref         0.0720
_reflns_Friedel_coverage         0.811
_reflns_Friedel_fraction_full    1.000
_reflns_Friedel_fraction_max     0.997
_reflns_number_gt                3847
_reflns_number_total             4487
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            ol500990f_si_003.cif
_cod_data_source_block           ca101213_0ma
_cod_depositor_comments
'Adding full bibliography for 1516147--1516149.cif.'
_cod_original_sg_symbol_H-M      'P 21'
_cod_database_code               1516148
_shelxl_version_number           2013-4
_shelx_estimated_absorpt_t_max   0.997
_shelx_estimated_absorpt_t_min   0.954
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups, All C(H,H) groups, All N(H) groups
 At 1.5 times of:
  All C(H,H,H) groups
2. Restrained distances
 N2-H2
 0.91 with sigma of 0.02
 N1-H1
 0.91 with sigma of 0.02
3.a Ternary CH refined with riding coordinates:
 C6(H6), C7(H7)
3.b Secondary CH2 refined with riding coordinates:
 C18(H18A,H18B)
3.c Aromatic/amide H refined with riding coordinates:
 C3(H3), C4(H4), C11(H11), C12(H12), C14(H14), C15(H15), C16(H16), C20(H20),
 C21(H21)
3.d Idealised Me refined as rotating group:
 C1(H1A,H1B,H1C), C13(H13A,H13B,H13C), C19(H19A,H19B,H19C)
;