(2SR,3SR,4RS)-tert-Butyl 2,3-di­hydroxy 4-(tert-butoxy­carbonyl)­amino­hexanoate

The reaction of γ-(N-t-butoxy­carbonyl)­amino-α,β-ethyl­enic esters with OsO₄ yields the corresponding α,β-di­hydroxy compounds with good diastereoselectivity. The crystal structure of the major stereomer, (2SR,3SR,4RS)-Me₂CHCH(NHCO₂^tBu)CHOHCHOHCO₂^tBu, C₁₆H₃₁NO₆, shows that the relative stereochemistry of the CHO–CHO–CHN sequence is anti–syn.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.046
• wR factor = 0.066
• Data-to-parameter ratio = 16.0

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT021_ALERT_1_C Ratio Unique / Expected Reflections too High ...       1.03
PLAT220_ALERT_2_C Large Non-Solvent    C     Ueq(max)/Ueq(min) ...       2.78 Ratio
PLAT242_ALERT_2_C Check Low    U(eq) as Compared to Neighbors ....         C5
PLAT242_ALERT_2_C Check Low    U(eq) as Compared to Neighbors ....        C13

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: CAD-4 Software (Enraf–Nonius, 1989); cell refinement: CAD-4 Software; data reduction: TEXSAN (MSC, 1992–1997); program(s) used to solve structure: SIR92 (Altomare et al.); program(s) used to refine structure: TEXSAN (Molecular Structure Corporation, 1992–1997)'; molecular graphics: 'ORTEPIII (Burnett & Johnson, 1996), ORTEP-3 for Windows (Farrugia, 1997) and CAMERON (Watkin et al., 1993)'; software used to prepare material for publication: TEXSAN (Molecular Structure Corporation, 1992–1997)'.

(I)

Crystal data

C16H31NO6	F(000) = 728.00
Mr = 333.42	Dx = 1.150 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.7107 Å
Hall symbol: -P 2ybc	Cell parameters from 25 reflections
a = 9.077 (4) Å	θ = 10.0–11.8°
b = 21.777 (5) Å	µ = 0.09 mm^−1
c = 10.19 (1) Å	T = 293 K
β = 107.02 (6)°	Prism, colorless
V = 1926 (2) Å^3	0.20 × 0.13 × 0.10 mm
Z = 4

Data collection

CAD-4 diffractometer	Rint = 0.011
Radiation source: X-ray tube	θmax = 30.0°, θmin = 2.1°
Graphite monochromator	h = 0→12
ω scans	k = −30→30
6037 measured reflections	l = −14→13
5752 independent reflections	2 standard reflections every 120 reflections
3323 reflections with I > 2.50σ(I)	intensity decay: 0.8%

Refinement

Refinement on F	0 restraints
Least-squares matrix: full	0 constraints
R[F^2 > 2σ(F^2)] = 0.046	H-atom parameters constrained
wR(F^2) = 0.066	Weighting scheme based on measured s.u.'s w = 1/[σ^2(Fo) + 0.00063|Fo|^2]
S = 1.69	(Δ/σ)max = 0.007
3323 reflections	Δρmax = 0.21 e Å^−3
208 parameters	Δρmin = −0.18 e Å^−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	1.23774 (15)	0.34949 (6)	0.95306 (12)	0.0506 (4)
O2	1.05591 (14)	0.35758 (5)	0.74863 (11)	0.0448 (3)
O3	1.07024 (15)	0.24006 (6)	0.95914 (13)	0.0528 (4)
O4	1.30846 (14)	0.25197 (6)	0.72612 (13)	0.0502 (4)
O5	0.92014 (14)	0.13885 (6)	0.79597 (12)	0.0512 (4)
O6	0.87433 (13)	0.13268 (6)	0.56408 (12)	0.0492 (4)
N1	1.11302 (14)	0.14091 (6)	0.69563 (13)	0.0372 (3)
C1	1.14410 (19)	0.32713 (8)	0.85540 (16)	0.0400 (4)
C2	1.11234 (18)	0.25870 (8)	0.84097 (16)	0.0395 (4)
C3	1.25801 (17)	0.22570 (8)	0.83295 (16)	0.0383 (4)
C4	1.23738 (17)	0.15582 (8)	0.81847 (16)	0.0377 (4)
C5	1.38452 (19)	0.12230 (8)	0.8151 (2)	0.0494 (5)
C6	1.3600 (3)	0.05351 (10)	0.8041 (3)	0.0757 (8)
C7	1.5187 (3)	0.13694 (13)	0.9387 (3)	0.1006 (9)
C8	1.0692 (2)	0.42503 (8)	0.73415 (17)	0.0455 (5)
C9	1.2211 (3)	0.43870 (11)	0.7093 (2)	0.0677 (7)
C10	1.0488 (3)	0.45845 (9)	0.8584 (2)	0.0571 (6)
C11	0.9349 (3)	0.43868 (10)	0.6087 (2)	0.0664 (7)
C12	0.96494 (18)	0.13769 (7)	0.69349 (16)	0.0374 (4)
C13	0.7064 (2)	0.14265 (10)	0.5282 (2)	0.0571 (6)
C14	0.6708 (3)	0.20134 (12)	0.5910 (3)	0.0941 (9)
C15	0.6612 (3)	0.14732 (17)	0.3742 (3)	0.1039 (10)
C16	0.6315 (2)	0.08841 (12)	0.5739 (3)	0.0721 (7)
H1	1.1284	0.1426	0.6148	0.075*
H2	1.0126	0.2062	0.9313	0.087*
H3	1.2303	0.2489	0.6438	0.092*
H21	1.0273	0.2507	0.7566	0.059*
H31	1.3357	0.2357	0.9190	0.061*
H41	1.2011	0.1411	0.8991	0.068*
H51	1.4103	0.1357	0.7357	0.059*
H61	1.2723	0.0446	0.7286	0.091*
H62	1.3436	0.0385	0.8862	0.091*
H63	1.4482	0.0343	0.7903	0.091*
H71	1.5981	0.1075	0.9462	0.121*
H72	1.4857	0.1355	1.0191	0.121*
H73	1.5566	0.1767	0.9290	0.121*
H91	1.2309	0.4148	0.6343	0.081*
H92	1.3026	0.4289	0.7892	0.081*
H93	1.2259	0.4811	0.6887	0.081*
H101	1.1402	0.4547	0.9329	0.069*
H102	1.0285	0.5006	0.8368	0.069*
H103	0.9648	0.4409	0.8832	0.069*
H111	0.9503	0.4185	0.5311	0.080*
H112	0.9281	0.4818	0.5930	0.080*
H113	0.8422	0.4244	0.6236	0.080*
H141	0.7055	0.1981	0.6884	0.113*
H142	0.7214	0.2346	0.5626	0.113*
H143	0.5626	0.2082	0.5622	0.113*
H151	0.7231	0.1773	0.3482	0.125*
H152	0.5558	0.1586	0.3404	0.125*
H153	0.6762	0.1086	0.3367	0.125*
H161	0.5226	0.0928	0.5415	0.086*
H162	0.6612	0.0518	0.5377	0.086*
H163	0.6631	0.0864	0.6713	0.086*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0548 (7)	0.0472 (7)	0.0412 (6)	−0.0023 (6)	0.0008 (5)	−0.0073 (5)
O2	0.0514 (7)	0.0379 (6)	0.0382 (6)	0.0015 (5)	0.0022 (5)	−0.0014 (5)
O3	0.0673 (8)	0.0516 (8)	0.0474 (7)	−0.0054 (6)	0.0291 (6)	−0.0050 (6)
O4	0.0530 (7)	0.0495 (7)	0.0533 (8)	−0.0110 (6)	0.0236 (6)	−0.0016 (5)
O5	0.0430 (7)	0.0687 (9)	0.0457 (7)	−0.0047 (6)	0.0189 (5)	0.0033 (6)
O6	0.0311 (6)	0.0711 (9)	0.0415 (6)	0.0003 (5)	0.0045 (5)	−0.0011 (6)
N1	0.0328 (7)	0.0447 (8)	0.0337 (6)	−0.0016 (5)	0.0091 (5)	−0.0026 (5)
C1	0.0421 (8)	0.0420 (9)	0.0351 (8)	0.0019 (7)	0.0101 (7)	−0.0042 (7)
C2	0.0421 (8)	0.0404 (9)	0.0340 (8)	0.0001 (7)	0.0078 (7)	−0.0020 (6)
C3	0.0364 (8)	0.0432 (9)	0.0333 (8)	−0.0023 (6)	0.0074 (6)	−0.0023 (6)
C4	0.0334 (7)	0.0417 (9)	0.0344 (8)	0.0014 (6)	0.0043 (6)	−0.0001 (6)
C5	0.0351 (9)	0.0469 (10)	0.0620 (12)	0.0051 (7)	0.0076 (8)	−0.0007 (8)
C6	0.0585 (13)	0.0506 (13)	0.114 (2)	0.0135 (10)	0.0186 (13)	−0.0017 (12)
C7	0.0496 (12)	0.098 (2)	0.122 (2)	0.0240 (13)	−0.0254 (13)	−0.0312 (17)
C8	0.0556 (10)	0.0391 (9)	0.0408 (9)	0.0002 (8)	0.0128 (8)	0.0021 (7)
C9	0.0722 (14)	0.0699 (15)	0.0672 (13)	−0.0051 (11)	0.0301 (11)	0.0028 (11)
C10	0.0775 (13)	0.0427 (10)	0.0538 (11)	0.0024 (9)	0.0235 (10)	−0.0039 (8)
C11	0.0798 (15)	0.0584 (13)	0.0520 (11)	0.0120 (10)	0.0054 (10)	0.0087 (9)
C12	0.0350 (7)	0.0353 (8)	0.0401 (8)	0.0004 (6)	0.0081 (6)	0.0024 (6)
C13	0.0319 (8)	0.0651 (13)	0.0649 (12)	0.0058 (8)	−0.0003 (8)	0.0084 (10)
C14	0.0634 (15)	0.0637 (16)	0.139 (3)	0.0238 (12)	0.0045 (15)	0.0024 (15)
C15	0.0564 (14)	0.169 (3)	0.0674 (15)	0.0014 (17)	−0.0120 (12)	0.0252 (17)
C16	0.0400 (10)	0.0751 (15)	0.0971 (18)	−0.0044 (10)	0.0138 (11)	−0.0019 (13)

Geometric parameters (Å, º)

O1—C1	1.2058 (19)	C7—H72	0.95
O2—C1	1.3245 (19)	C7—H73	0.95
O2—C8	1.485 (2)	C8—C9	1.503 (3)
O3—C2	1.424 (2)	C8—C10	1.518 (3)
O3—H2	0.90	C8—C11	1.515 (3)
O4—C3	1.419 (2)	C9—H91	0.95
O4—H3	0.93	C9—H92	0.95
O5—C12	1.227 (2)	C9—H93	0.95
O6—C12	1.3385 (19)	C10—H101	0.95
O6—C13	1.476 (2)	C10—H102	0.95
N1—C4	1.456 (2)	C10—H103	0.95
N1—C12	1.340 (2)	C11—H111	0.95
N1—H1	0.88	C11—H112	0.95
C1—C2	1.517 (2)	C11—H113	0.95
C2—C3	1.528 (2)	C13—C14	1.507 (4)
C2—H21	0.99	C13—C15	1.504 (3)
C3—C4	1.535 (2)	C13—C16	1.503 (3)
C3—H31	0.98	C14—H141	0.95
C4—C5	1.531 (2)	C14—H142	0.95
C4—H41	1.02	C14—H143	0.95
C5—C6	1.514 (3)	C15—H151	0.95
C5—C7	1.508 (3)	C15—H152	0.95
C5—H51	0.95	C15—H153	0.95
C6—H61	0.95	C16—H161	0.95
C6—H62	0.95	C16—H162	0.95
C6—H63	0.95	C16—H163	0.95
C7—H71	0.95
O1···H1^i	2.16	O1···N1^i	3.0116 (19)
O1···N1^i	3.0116 (19)	O3···O5	2.8551 (19)
O3···H3^i	2.03	O3···O4^i	2.943 (2)
O3···O4^i	2.943 (2)	O4···N1	2.9619 (18)
O5···H111^i	2.645	O5···N1	2.2715 (19)
O1···O2	2.2540 (16)	O5···O6	2.2795 (17)
O1···O3	2.8373 (19)	O6···N1	2.1958 (18)
C1—O2—C8	121.98 (12)	C9—C8—C10	112.81 (16)
C2—O3—H2	104.0	C9—C8—C11	111.76 (17)
C3—O4—H3	109.3	C10—C8—C11	110.14 (16)
C12—O6—C13	121.62 (14)	C8—C9—H91	109.5
C4—N1—C12	123.20 (14)	C8—C9—H92	109.5
C4—N1—H1	120.1	C8—C9—H93	109.4
C12—N1—H1	115.0	H91—C9—H92	109.5
O1—C1—O2	125.88 (16)	H91—C9—H93	109.5
O1—C1—C2	123.01 (15)	H92—C9—H93	109.5
O2—C1—C2	111.11 (13)	C8—C10—H101	109.4
O3—C2—C1	106.76 (13)	C8—C10—H102	109.5
O3—C2—C3	111.20 (13)	C8—C10—H103	109.4
O3—C2—H21	110.5	H101—C10—H102	109.5
C1—C2—C3	108.92 (14)	H101—C10—H103	109.4
C1—C2—H21	109.6	H102—C10—H103	109.5
C3—C2—H21	109.8	C8—C11—H111	109.5
O4—C3—C2	109.27 (13)	C8—C11—H112	109.4
O4—C3—C4	112.57 (13)	C8—C11—H113	109.5
O4—C3—H31	106.7	H111—C11—H112	109.5
C2—C3—C4	112.85 (13)	H111—C11—H113	109.6
C2—C3—H31	104.8	H112—C11—H113	109.4
C4—C3—H31	110.1	O5—C12—O6	125.36 (15)
N1—C4—C3	110.24 (12)	O5—C12—N1	124.49 (15)
N1—C4—C5	109.62 (13)	O6—C12—N1	110.15 (14)
N1—C4—H41	105.6	O6—C13—C14	110.77 (16)
C3—C4—C5	113.08 (14)	O6—C13—C15	102.40 (17)
C3—C4—H41	107.1	O6—C13—C16	109.65 (16)
C5—C4—H41	110.9	C14—C13—C15	111.1 (2)
C4—C5—C6	111.23 (15)	C14—C13—C16	111.2 (2)
C4—C5—C7	112.11 (18)	C15—C13—C16	111.4 (2)
C4—C5—H51	107.9	C13—C14—H141	109.4
C6—C5—C7	109.60 (18)	C13—C14—H142	109.7
C6—C5—H51	108.0	C13—C14—H143	109.6
C7—C5—H51	107.8	H141—C14—H142	109.4
C5—C6—H61	109.4	H141—C14—H143	109.1
C5—C6—H62	109.5	H142—C14—H143	109.6
C5—C6—H63	109.5	C13—C15—H151	109.7
H61—C6—H62	109.4	C13—C15—H152	109.6
H61—C6—H63	109.4	C13—C15—H153	109.3
H62—C6—H63	109.6	H151—C15—H152	109.8
C5—C7—H71	109.3	H151—C15—H153	109.4
C5—C7—H72	109.2	H152—C15—H153	109.2
C5—C7—H73	109.7	C13—C16—H161	109.5
H71—C7—H72	109.2	C13—C16—H162	109.5
H71—C7—H73	109.7	C13—C16—H163	109.4
H72—C7—H73	109.7	H161—C16—H162	109.5
O2—C8—C9	108.55 (15)	H161—C16—H163	109.4
O2—C8—C10	110.97 (14)	H162—C16—H163	109.5
O2—C8—C11	102.09 (14)

Symmetry code: (i) x, −y+1/2, z+1/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H2···O5	0.90	2.02	2.8551 (19)	154
N1—H1···O1^ii	0.88	2.17	3.012 (2)	163
O4—H3···O3^ii	0.93	2.03	2.943 (2)	169

Symmetry code: (ii) x, −y+1/2, z−1/2.