Spiro,4.4 nonane-1,6-diol

Spiro[4.4]nonane-1,6-diol, 343 Spiro[4.4]nonane-l,6-dione, 396, 397 Spiro[4.4]nonatetraene, 357-358 Spiro[4.4 ] nona-1,3,7-triene, 457... 

Synthesis of olefins from stericaUy hindered alcohols. Gerlach et al. have reported a successful variation of the Chugaev reaction applicable to the preparation of temperature-sensitive olefins from sterically hindered alcohols. Thus /ran.v./ran.v-spiro[4.4]nonane-1,6-diol (2) is converted into the thiocarbonate O-ester (3) by reaction with (1) in pyridine for 4 hr. at room temperature (80% yield). This derivative decomposes smoothly into the diene, 1,6-spiro[4.4]nonadiene (4), at a temperature of > 135°. In this case pyrolysis of the diacetate or of the di-S-methylxanthate failed to give the diene. 

Figure 1 Spiro[4,4]nonane- 1,6-diol and related chiral auxiliaries...

Spiro[4.4]nonane-1,6-diol has been selectively prepared by hydrogenation of the corresponding spiro diketone (Scheme 2.82) [55]. The latter is available by the alkylation of diethyl malonate with y-bromo butyrate. Saponification of the tetraester and successive treatment with an acid, acetic anhydride, and heat produce the diketone. By using a Ru(BINAP) catalyst for the final hydrogenation of... 

Scheme 2.82 Synthesis of c s,frans-spiro[4.4]nonane-1,6-diol.

Several aliphatic or aromatic diols were employed for the construction of the backbone, such as l-benzyl-3,4-dihydroxypyrrolidine-2,5-dione, enan-tiopure binaphthols or achiral biphenols, brenzcatechol, aliphatic diols, or spiro[4.4]nonane-1.6-diol (see also Section 2.2.2) [44-47]. Three-carbon bridged diols proved to be more effective compared to two-carbon or four-carbon bridged analogs, which has been explained by a counterproductive fluxional behavior in the corresponding rhodium complexes [48]. Diphosphites based on 1,3-diphenylpropane also produced iirferior enantioselectivities in comparison to the 2,4-pentanediol backbone of Chiraphite. For the design of both side arms, it was concluded that a diphosphite based on the unsubstituted biphenol is less suited... 

R)-2,2 -Dihydroxy-1,1 -binaphthyl [3] was examined in the O-H stretching region and from 950 to 1700 cm h For (IR, 5R, 6R)-(-)-spiro[4.4]nonane-1,6-diol [4], the theoretical VCD spectra were produced using vibronic coupling theory at the 6-3IG level. A comparison of the crystal structure of the ketal of the compound with optically pure (+)-(5(2-cholestan-3-one confirmed the results of the VCD determination. 

A chiral diphosphite based on binaphthol, coordinated with rhodium (I) forming a nine-member ed ring, led to an efficient hydroformylation of vinylarenes, although moderate ees were obtained (up to 46%) at mild pressure and temperature reaction conditions.364 Chiral diphosphites and phosphinite-phosphites derived from spiro[4.4]nonane-l,6-diol were synthesized. Using these catalysts in the asymmetric hydroformylation of styrene, high regioselectivity (97%) and... 

Nieman and Keay198 reported the use of c/.v,c/s-spiro 4,4]nonanc-1, 6-diol as a new chiral auxiliary to be used in asymmetric Diels-Alder reactions. Their best results in a series of reactions between chiral acrylates and cyclopentadiene were obtained when the pivalate ester of ds,ds-spiro[4,4]nonane-l,6-diol was used as the chiral auxiliary. When 318 was treated with cyclopentadiene, the expected endo adduct 319 was obtained with more than 97% de (equation 88). 

The absolute configuration of (-)-spiro[4.4]nonane-l,6-dione was determined by application of Horeau s method of optical rotations.[45] In support of the assignment, and with greater certainty, the Exciton Chirality Rule was applied to the bis-p-dimethylamino-benzoate of the cis,trans-diol obtained following reduction of the diketone. The cis,trans-diol is readily distinguished by NMR from the C2-symmetry cis,cis and rrans,rrans-diols. Since the cis,trans-diol dibenzoate from the (-)-dione exhibits a (-) exciton chirality CD, it follows that the absolute configuration of the dione is that shown in Figure 37. The absolute stereochemistry is easily determined by CD. 

Figure 37. (a) Formation of the ds,trans-diol of (-)-spiro[4.4]nonane-l,6-dione. (b) Observed CD of the bis-p-dimethylaminobenzoate of the cis,trans-diol. (c) Exciton chirality. 

Dioxa-spiro[4.4 nonan 6-Brom-E14a/1, 221 (Keton/Diol/Br2)... 

To 150 mL liquid ammonia at -78°C, were added 0.3 g sodium in small pieces (12.0 mmol, 6.0 eq.). After 15 min, a solution of ( )-(lR5,25 R)-methyl l-(but-3-enyl)-2-hydroxycyclopentane-1 -carboxylate (2.0 mmol, 1.0 eq.) in 5 mL THF was added dropwise. The reaction mixture was warmed to -33°C and stirred in refluxing ammonia for 10 min. The excess of sodium was then destroyed by the addition of ammonium chloride, and the ammonia was evaporated under a stream of nitrogen (fume hood). Et20 was added, and the reaction mixture was neutralized by a solution of 10% HCl. The residue was extracted with Et20. The organic layers were dried over MgS04 and filtered the solvent was removed in vacuo. The cmde oil was purified by crystallization in pentane, and 95% ( )-(lSR,2RS,5SR,6RS)-2-methyl-spiro[4.4]nonane-l,6-diol was obtained, m.p. 132 - 133°C,R/= 0.10 (petroleum ether/EtOAc = 50 50). 

Phenylpropane-l,2-diols, A21.1, A21.2, A"16 Spiro[4.4]nonane-l, 6-dione, X 3.9 Norbornenecarboxylic acids, methyl esters,... 

The VCD spectrum of each of the six lowest energy conformers of cis,cis spiro[4,4]nonane-l,6 diol 27 was calculated at the VCT/SCF level in the DO gauge using the basis set. The simulated spectrum shown in Figure... 

Chem., 60, 1918 (1995). Determining Absolute Configuration by Spectroscopic Means The Vibrational Circular Dichroism Spectrum of (+)-(lS,5S,6S)- and -)- iR,SR,6R)-Spiro[4.4]nonane l,6-diol. 

Compounds l-azabicyclo[3.1.0]hexane 17 and 2-carbomethoxyaziridine 18 were synthesized by G. V. Shustov and A. uk, and c>s,c>s-spiro[4,4]nonane-l,6>diol 27 by J. A. Nieman and B. A. Keay in the Department of Chemistry at the University of Calgary. The experimental spectra were measured by D. Tsankov in the laboratory of H. Wieser in the Department of Chemistry at the University of Calgary. IR and VCD spectra were recorded in the CCI4 solution in a 0.15 mm NaCl cell on a Bomem MBIOO spectrometer at 4 cm resolution. For 1 -azabicydo[3.1.0]hexane 17 and 2-carbomethoxyaziridine 18,250 scans were collected for IR spectra and 5000 scans were collected for VCD spectra. For c/s,cis-spiro[4,4]nonane-l,6-diol 27, 500 scans were collected for IR spectra and 10,000 scans were collected for VCD spectra. The concentrations used are 1.28 M for l-azabicyclo[3.1.0]hexane 17,0.1174 M for 2-carbomethoxyaziridine, and 1.29 M for C(s,eis-spiro[4,4]nonane-l,6-diol 27. 

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