4,5,7,8-Tetra­hydro-2-(2-propenyl)-6H-[1,3,6,2]­diox­aza­borocine

In the title compound, C₇H₁₄BNO₂, the B—N distance is 1.659 (4) Å. Molecules are linked through intermolecular N—H...O hydrogen bonds to form infinite chains with an N...O distance of 2.907 (3) Å.

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.063
• wR factor = 0.176
• Data-to-parameter ratio = 16.5

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level C:



RINTA_01  Alert C The value of Rint is greater than 0.10
          Rint given   0.138


 0 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 1 Alert Level C = Please check

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S1. Comment

The reaction of allylboron reagents and its derivatives with carbonyl compounds is one of the most important reactions in organic synthesis. Many allylboron compounds, however, are sensitive to air and/or moisture and require special handling procedures. In view of this, the development of stable variants of allylboronic acid is an important task. We have recently synthesized potassium allyltrifluoroborate and demonstrated its synthetic utility in aqueous and organic media (Batey et al., 2000; Batey & Thadani, 2001). The title compound, (I), is another stable variant that reacts with aldehydes to afford the corresponding homoallylic alcohols in moderate to good yields in dichloromethane. Both potassium allyltrifluoroborate and (I) are stable to air and/or moisture and can be stored for extended periods without any special precautions.

Molecules of (I) are linked by hydrogen bonds to form infinite chains through glide-plane transformations along the c axes, with a distance for N1···O1 of 2.903 (3) Å (see Fig. 2 and Table 2). A search of the April 2001 release of the Cambridge Structural Database (Allen & Kennard, 1993) revealed the structures of four other dioxazaborocine compounds [with refcodes COQRAB (Doidge-Harrison et al., 1998), PBORXZ (Rettig & Trotter, 1975), PUTBUB (Caron & Hawkins, 1998) and SIBGIT (Howie et al., 1997)]. The B—N distance in these compounds ranges from 1.657 to 1.672 Å and in (I), the B1—N1 distance is 1.659 (4) Å. [Dear Alan, I have added the references for the refcodes as this is required by Acta journals. I would be grateful if you would check that they are correct and provide final page numbers if possible – Sean]

S2. Experimental

To a solution of allylboronic acid (Brown et al., 1990) (1 equivalent) in a minimal amount of ⁱPrOH was added diethanolamine (1 equivalent). The reaction mixture was stirred for 2 h at room temperature. The solvent was then removed under reduced pressure and the resulting solid recrystallized from acetonitrile. The title compound was obtained in 66% yield as clear colourless needles.

S3. Refinement

H atoms were included in calculated positions with C—H distances ranging from 0.95 to 0.99 Å and an N—H distance of 0.93 Å.

Computing details

Data collection: COLLECT (Nonius, 1997-2001); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997); data reduction: DENZO-SMN; program(s) used to solve structure: SHELXTL (Sheldrick, 1999); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. View of (I) showing the atom-labelling scheme. Ellipsoids are at the 50% probability level. H atoms bonded to C atoms have been removed for the sake of clarity.
	Fig. 2. View of the hydrogen bonding in (I) showing infinite chains in the z direction. Ellipsoids are at the 50% probability level. H atoms bonded to C atoms have been removed for the sake of clarity.

4,5,7,8-Tetrahydro-2-(2-Propenyl)-6H-[1,3,6,2]-dioxazaborocine

Crystal data

C7H14BNO2	F(000) = 672
Mr = 155.00	Dx = 1.231 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 21.1480 (17) Å	Cell parameters from 6734 reflections
b = 8.5399 (11) Å	θ = 4.1–26.2°
c = 9.4229 (10) Å	µ = 0.09 mm^−1
β = 100.524 (7)°	T = 100 K
V = 1673.2 (3) Å^3	Needle, colorless
Z = 8	0.40 × 0.10 × 0.07 mm

Data collection

Nonius Kappa-CCD diffractometer	1668 independent reflections
Radiation source: fine-focus sealed tube	978 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.138
Detector resolution: 9 pixels mm^-1	θmax = 26.2°, θmin = 4.1°
ϕ scans and ω scans with κ offsets	h = −26→26
Absorption correction: multi-scan (DENZO-SMN; Otwinowski & Minor, 1997)	k = −10→10
Tmin = 0.966, Tmax = 0.994	l = −11→11
6735 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.063	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.176	H-atom parameters constrained
S = 0.99	w = 1/[σ^2(Fo^2) + (0.0903P)^2] where P = (Fo^2 + 2Fc^2)/3
1668 reflections	(Δ/σ)max < 0.001
101 parameters	Δρmax = 0.28 e Å^−3
0 restraints	Δρmin = −0.33 e Å^−3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	Uiso*/Ueq
O1	0.41836 (8)	0.0141 (2)	0.5642 (2)	0.0274 (5)
O2	0.30289 (9)	0.0089 (3)	0.4862 (2)	0.0316 (6)
N1	0.37166 (10)	−0.0895 (3)	0.3277 (2)	0.0260 (6)
H1C	0.3760	−0.0462	0.2395	0.031*
C1	0.36857 (13)	0.2228 (3)	0.3826 (3)	0.0303 (7)
H1A	0.4116	0.2389	0.3575	0.036*
H1B	0.3361	0.2331	0.2930	0.036*
C2	0.35697 (13)	0.3458 (4)	0.4873 (3)	0.0310 (7)
H2A	0.3134	0.3649	0.4947	0.037*
C3	0.40050 (15)	0.4301 (4)	0.5700 (4)	0.0393 (8)
H3A	0.4448	0.4156	0.5668	0.047*
H3B	0.3879	0.5058	0.6332	0.047*
C4	0.43536 (13)	−0.1462 (4)	0.5535 (3)	0.0299 (7)
H4A	0.4052	−0.2148	0.5935	0.036*
H4B	0.4795	−0.1657	0.6065	0.036*
C5	0.43104 (12)	−0.1760 (4)	0.3935 (3)	0.0273 (7)
H5A	0.4692	−0.1344	0.3591	0.033*
H5B	0.4269	−0.2893	0.3713	0.033*
C6	0.26518 (13)	−0.0741 (4)	0.3716 (3)	0.0336 (8)
H6A	0.2446	−0.0010	0.2955	0.040*
H6B	0.2312	−0.1346	0.4067	0.040*
C7	0.31068 (12)	−0.1828 (4)	0.3135 (3)	0.0283 (7)
H7A	0.3176	−0.2803	0.3710	0.034*
H7B	0.2940	−0.2099	0.2114	0.034*
B1	0.36479 (14)	0.0496 (4)	0.4468 (4)	0.0271 (8)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0306 (10)	0.0247 (12)	0.0270 (11)	0.0029 (8)	0.0056 (8)	−0.0009 (9)
O2	0.0298 (11)	0.0362 (13)	0.0306 (12)	−0.0033 (8)	0.0099 (8)	−0.0060 (10)
N1	0.0287 (12)	0.0253 (15)	0.0251 (14)	0.0000 (10)	0.0078 (9)	−0.0003 (10)
C1	0.0314 (15)	0.0296 (18)	0.0311 (17)	0.0050 (12)	0.0092 (12)	0.0019 (14)
C2	0.0350 (15)	0.0248 (17)	0.0345 (17)	0.0033 (13)	0.0100 (12)	0.0026 (14)
C3	0.0457 (18)	0.0278 (19)	0.046 (2)	0.0017 (14)	0.0117 (15)	0.0001 (15)
C4	0.0326 (15)	0.0269 (18)	0.0299 (17)	0.0027 (12)	0.0052 (12)	−0.0012 (13)
C5	0.0242 (14)	0.0276 (17)	0.0308 (16)	0.0028 (12)	0.0071 (11)	−0.0015 (13)
C6	0.0314 (15)	0.0363 (19)	0.0336 (18)	−0.0003 (13)	0.0073 (12)	−0.0041 (14)
C7	0.0316 (14)	0.0257 (17)	0.0284 (16)	−0.0032 (12)	0.0079 (11)	−0.0021 (12)
B1	0.0271 (17)	0.028 (2)	0.0261 (18)	0.0007 (13)	0.0046 (13)	−0.0061 (14)

Geometric parameters (Å, º)

O1—C4	1.424 (4)	C2—H2A	0.9500
O1—B1	1.463 (4)	C3—H3A	0.9500
O2—C6	1.411 (3)	C3—H3B	0.9500
O2—B1	1.466 (4)	C4—C5	1.515 (4)
N1—C5	1.491 (3)	C4—H4A	0.9900
N1—C7	1.501 (3)	C4—H4B	0.9900
N1—B1	1.659 (4)	C5—H5A	0.9900
N1—H1C	0.9300	C5—H5B	0.9900
C1—C2	1.492 (4)	C6—C7	1.510 (4)
C1—B1	1.606 (4)	C6—H6A	0.9900
C1—H1A	0.9900	C6—H6B	0.9900
C1—H1B	0.9900	C7—H7A	0.9900
C2—C3	1.308 (4)	C7—H7B	0.9900
C4—O1—B1	108.4 (2)	H4A—C4—H4B	108.8
C6—O2—B1	109.3 (2)	N1—C5—C4	102.9 (2)
C5—N1—C7	114.8 (2)	N1—C5—H5A	111.2
C5—N1—B1	104.16 (19)	C4—C5—H5A	111.2
C7—N1—B1	105.11 (19)	N1—C5—H5B	111.2
C5—N1—H1C	110.8	C4—C5—H5B	111.2
C7—N1—H1C	110.8	H5A—C5—H5B	109.1
B1—N1—H1C	110.8	O2—C6—C7	106.1 (2)
C2—C1—B1	112.0 (2)	O2—C6—H6A	110.5
C2—C1—H1A	109.2	C7—C6—H6A	110.5
B1—C1—H1A	109.2	O2—C6—H6B	110.5
C2—C1—H1B	109.2	C7—C6—H6B	110.5
B1—C1—H1B	109.2	H6A—C6—H6B	108.7
H1A—C1—H1B	107.9	N1—C7—C6	103.6 (2)
C3—C2—C1	126.8 (3)	N1—C7—H7A	111.0
C3—C2—H2A	116.6	C6—C7—H7A	111.0
C1—C2—H2A	116.6	N1—C7—H7B	111.0
C2—C3—H3A	120.0	C6—C7—H7B	111.0
C2—C3—H3B	120.0	H7A—C7—H7B	109.0
H3A—C3—H3B	120.0	O1—B1—O2	111.3 (2)
O1—C4—C5	105.2 (2)	O1—B1—C1	113.0 (2)
O1—C4—H4A	110.7	O2—B1—C1	115.0 (2)
C5—C4—H4A	110.7	O1—B1—N1	102.2 (2)
O1—C4—H4B	110.7	O2—B1—N1	101.2 (2)
C5—C4—H4B	110.7	C1—B1—N1	112.8 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1C···O1^i	0.93	2.04	2.907 (3)	155

Symmetry code: (i) x, −y, z−1/2.