Concerted synthesis of a spirobicyclic type-VI beta-turn mimic of Pro-Pro-Pro-NH2.
Vartak, Ashish P.; Johnson, Rodney L.; Organic letters 8 (2006) 983–986; doi:10.1021/ol0600335

data_1505885
_publ_section_title
;
 Concerted synthesis of a spirobicyclic type-VI beta-turn mimic of
 Pro-Pro-Pro-NH2.
;
_journal_issue                   5
_journal_name_full               'Organic letters'
_journal_page_first              983
_journal_page_last               986
_journal_paper_doi               10.1021/ol0600335
_journal_volume                  8
_journal_year                    2006
_chemical_absolute_configuration rm
_chemical_formula_moiety         'C20 H34 N2 O4'
_chemical_formula_sum            'C20 H34 N2 O4'
_chemical_formula_weight         366.49
_chemical_name_common            05114
_chemical_name_systematic
;
(2R,5R,1'R)-2-tert-Butyl-5-(2',2'-dimethyl-1-(2S-carboxy-1-pyrrolidinyl)
propyl-1-aza-3-oxabicyclo[3.3.0]octan-4-one (16)
;
_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   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   6.7041(11)
_cell_length_b                   12.864(2)
_cell_length_c                   23.295(4)
_cell_measurement_reflns_used    2503
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      26.74
_cell_measurement_theta_min      2.36
_cell_volume                     2009.0(6)
_computing_cell_refinement       'SAINT, Bruker'
_computing_data_collection       'SMART, Bruker'
_computing_data_reduction        'SAINT, Bruker'
_computing_molecular_graphics    'SHELXTL, Bruker'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      173(2)
_diffrn_measured_fraction_theta_full 0.995
_diffrn_measured_fraction_theta_max 0.995
_diffrn_measurement_device_type  'Siemens SMART Platform CCD'
_diffrn_measurement_method       'area detector, omega scans per phi'
_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  0.0325
_diffrn_reflns_av_sigmaI/netI    0.0265
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       16
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       29
_diffrn_reflns_limit_l_min       -30
_diffrn_reflns_number            12634
_diffrn_reflns_theta_full        27.49
_diffrn_reflns_theta_max         27.49
_diffrn_reflns_theta_min         1.75
_exptl_absorpt_coefficient_mu    0.084
_exptl_absorpt_correction_T_max  0.9958
_exptl_absorpt_correction_T_min  0.9753
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS, R. Blessing, 1995'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.212
_exptl_crystal_density_meas      0
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             800
_exptl_crystal_size_max          0.30
_exptl_crystal_size_mid          0.18
_exptl_crystal_size_min          0.05
_refine_diff_density_max         0.167
_refine_diff_density_min         -0.168
_refine_diff_density_rms         0.040
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0(10)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.026
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     245
_refine_ls_number_reflns         2634
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.026
_refine_ls_R_factor_all          0.0482
_refine_ls_R_factor_gt           0.0361
_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^)+(0.0510P)^2^+0.2740P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0849
_refine_ls_wR_factor_ref         0.0907
_reflns_number_gt                2224
_reflns_number_total             2634
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol0600335si20060106_023819.cif
_cod_data_source_block           05114
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Orthorhombic' changed to
'orthorhombic' according to
/home/saulius/struct/CIF-dictionaries/cif_core.dic dictionary named
'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_values 1715 2011-07-08 13:25:40Z adriana 
;
_cod_original_sg_symbol_H-M      P2(1)2(1)2(1)
_cod_database_code               1505885