Enantioselective Synthesis of α-Quaternary Amino Acid Derivatives by Sequential Enzymatic Desymmetrization and Curtius Rearrangement of α,α-Disubstituted Malonate Diesters
Violeta Iosub; Anton R. Haberl; Jennifer Leung; Michael Tang; Kannan Vembaiyan; Masood Parvez; Thomas G. Back; Journal of Organic Chemistry 75 (2010) 1612–1619; doi:10.1021/jo902584r

data_4025273
_publ_contact_author
;
    Masood Parvez
    Department of Chemistry
    University of Calgary
    2500 University Drive N.W.
    Calgary, Alberta, Canada T2N 1N4  
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_publ_contact_author_email       ' parvez@ucalgary.ca '
_publ_contact_author_fax         ' (403)289-9488 '
_publ_contact_author_phone       ' (403)220-5348 '
_publ_section_title
;
 Enantioselective Synthesis of \a-Quaternary Amino Acid Derivatives by
 Sequential Enzymatic Desymmetrization and Curtius Rearrangement of
 \a,\a-Disubstituted Malonate Diesters
;
_journal_name_full               'Journal of Organic Chemistry'
_journal_page_first              1612
_journal_page_last               1619
_journal_paper_doi               10.1021/jo902584r
_journal_volume                  75
_journal_year                    2010
_chemical_absolute_configuration syn
_chemical_formula_moiety         'C25 H34 N2 O3'
_chemical_formula_sum            'C25 H34 N2 O3'
_chemical_formula_weight         410.54
_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            8
_cell_length_a                   11.5059(4)
_cell_length_b                   18.5068(6)
_cell_length_c                   22.2217(6)
_cell_measurement_reflns_used    32823
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      68.1
_cell_measurement_theta_min      3.1
_cell_volume                     4731.8(3)
_computing_cell_refinement       'APEX2 (Bruker, 2004)'
_computing_data_collection       'APEX2 (Bruker, 2004)'
_computing_data_reduction        'SAINT & XPREP (Bruker, 2004)'
_computing_molecular_graphics    'ORTEP-3 (Farrugia, 1997)'
_computing_publication_material  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS (Sheldrick, 2008)'
_diffrn_ambient_temperature      173(2)
_diffrn_measured_fraction_theta_full 0.989
_diffrn_measured_fraction_theta_max 0.989
_diffrn_measurement_device_type  'Bruker APEX2 CCD'
_diffrn_measurement_method       ' \w and \f '
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.1271
_diffrn_reflns_av_sigmaI/netI    0.0809
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       18
_diffrn_reflns_limit_k_min       -22
_diffrn_reflns_limit_l_max       25
_diffrn_reflns_limit_l_min       -20
_diffrn_reflns_number            32823
_diffrn_reflns_theta_full        68.1
_diffrn_reflns_theta_max         68.1
_diffrn_reflns_theta_min         3.1
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.596
_exptl_absorpt_correction_T_max  0.9483
_exptl_absorpt_correction_T_min  0.8900
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS: (Bruker, 2004)'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.153
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             1776
_exptl_crystal_size_max          0.20
_exptl_crystal_size_mid          0.19
_exptl_crystal_size_min          0.09
_refine_diff_density_max         0.19
_refine_diff_density_min         -0.20
_refine_diff_density_rms         0.042
_refine_ls_abs_structure_details
'An absolute structure could not be established'
_refine_ls_extinction_coef       0.00152(14)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   1.019
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     548
_refine_ls_number_reflns         4754
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.019
_refine_ls_R_factor_all          0.0711
_refine_ls_R_factor_gt           0.0446
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0233P)^2^+0.7903P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0986
_refine_ls_wR_factor_ref         0.1141
_reflns_number_gt                3501
_reflns_number_total             4754
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            jo902584r_si_003.cif
_cod_data_source_block           Compound_I
_cod_depositor_comments
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The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Orthorhombic' changed to
'orthorhombic' according to the built-in table from CIF Core
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_values 1646 2011-03-28 12:23:43Z adriana 
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_cod_database_code               4025273