Reactions of dimethyl acetylenedicarboxylate—X: Reaction with salicylaldehyde,ortho hydroxyacetophenone, 2-hydroxychalcones and 2,2′-dihydroxychalcones

Salicylaldehyde reacts with dimethyl acetylenedicarboxylate in benzene solution to give a mixture of dimethyl o-formylphenoxymaleate, dimethyl o-formylphenoxyfumarate, 2,3-dicarbomethoxychrom - 2 - en - 4 - ol, 2,3 - dicarbomethoxychrom - 3 - en - 2 - ol, dimethyl (2,3 - dicarbomethoxychrom - 2 - en - 4 - yl) - oxalacetate and dimethyl fumarate. 2,3 - Dicarbomethoxychrom - 3 - en - 2 - ol in this reaction is formed from 2,3 - dicarbomethoxychrom - 2 - en - 4 - ol through a benzopyrylium intermediate. The reaction of salicylaldehyde with excess of dimethyl acetylenedicarboxylate, however, gives a mixture of 2,3 - dicarbomethoxychrom - 3 - en - 2 - ol and dimethyl (2,3 - dicarbomethoxychrom - 3 - en) - 2 - oxyfumarate. 2,3 - Dicarbomethoxychrom - 3 - en - 2 - ol itself reacts further with dimethyl acetylenedicarboxylate to give 2,3,12 - tricarbomethoxychrom - 3,4 - eno[2,3 - b] pyrone. Similarly, the reaction of o-hydroxyacetophenone with dimethyl acetylendicarboxylate gives a mixture of dimethyl o-acetylphenoxymaleate, dimethyl o-acetylphenoxyfumarate, 2,3 - dicarbomethoxy - 4 - methylchrom - 2 - en - 4 - ol and 2,3 - dicarbomethoxy - 4 - methylchrom - 3 - en - 2 - ol. Both 2-hydroxychalcone and 2 - hydroxy - 4′ - methoxychalcone give mixtures of chalcone - 2 - oxymaleate and chalcone - 2 - oxyfumarate. The reaction of 2,2t?-dihydroxychalcone, however, gives 2′-hydroxyflavone, in addition to the expected maleate and fumarate. Similar reactions of 5 - chloro - 2,2′ - dihydroxychalcone and of 3,5 - dibromo - 2,2′ - dihydroxychalcone, on the other hand, give 2,3 - dicarbomethoxy - 4 - (o - hydroxyphenacyl) - 6 - chlorochrom - 2 - ene and 2,3 - dicarbomethoxy - 4 - (o - hydroxyphenacyl) 6,8 - dibromochrom - 2 - ene, respectively, together with the corresponding maleates and fumarates.     

Generation of simple methylenecyclopropenes as reactive intermediates

The dehydrochlorination of either 1,2 - dichloro - 1 - methylcyclopropane or 1 - bromo - 2 - chloro - 2 - methylcyclopropane with potassium t-butoxide yields 2 - t - butoxy - 1 - methylenecyclopropane. These results are interpreted in terms of methylenecyclopropene as a reactive intermediate which is trapped by addition of nucleophile (t-butoxide) to the cyclopropenyl double bond. The introduction of methanethiol to the reaction medium yields 2 - thiomethyl - 1 - methylenecyclopropene 2,2 - Dichloro - 1 - methylenecyclopropane reacts with potassium t-butoxide in tetrahydrofuran to yield trans- and cis - t - butoxybut - 1 - ene - 3 - yne. The addition of thiomethide ion results in the formation of 2,2 - bis(thiomethyl) - 1 - methylenecyclopropane and 2 - t - butoxy - 2 - thiomethyl - 1 - methylenecyclopropane. Other evidence for simple methylenecyclopropenes as reactive intermediates comes from the observation that nucleophiles add nonregiospecifically to the reactive intermediate produced by the dehydrohalogenation of 2 - halo - 1 - alkylidenecyclopropanes. Novel methylenecyclopropane→ cyclopropene transformations were found in the reaction of 2 - halomethylenecyclopropanes with thiomethide ion.     

Synthesis of the pentasaccharide repeating unit of the O-specific polysaccharide from salmonella strasbourg

The pentasaccharide α - Tyv - (1→3) - β - d - Man - (1→4) - α - l - Rha - (1→3) - d - Gal - (4←1) -α - d - Glc 1, the repeating unit of the O-specific polysaccharide chain of the lipopolysaccharide from S. Strasbourg, was obtained by glycosylation of benzyl - 2,6 - di - O - benzyl - 4 - O - (2,3,4 - tri - O - benzyl - 6 - O - benzoyl - α - d - glucopyranosyl) - β - d - galactopyranoside with 1,2 - methylorthoacetyl - 3 - O - acetyl - 4- O - [3 - O - (2,4 - di - O - acetyl - 3, 6 - dideoxy,- α - d - arabino - hexopyranosyl) - 2,4,6 - tri - O - acetyl - β - d - mannopyranosyl] - β - l - rhamnopyranose 3 followed by removal of protecting groups. The structure of the synthetic pentasaccharide was proved by methylation analysis and ¹³C NMR.     

Separation techniques in speciation analysis for organometallic species

A comprehensive review of the state-of-the-art of the separation of various organically-bound metals and metalloids for speciation analysis is presented. Recent developments in chromatographic (gas, liquid and supercritical fluid), electrophoretic (free-flow and gel) and fractionation techniques are discussed, followed by a survey of pertinent applications to speciation analysis for organometals and metalloids. The required sample characteristics for a given separation technique are specified and appropriate derivatization procedures are characterized. Methods applicable to the speciation of organic species of a particular element in various matrices are critically evaluated.List of abbreviations APS ammonium pentanesulfonate - CCC counter current chromatography - CZE capillary zone electrophoresis - DBT dibutyltin - DCyT dicyclohexyltin - DDTC diethyldithicarbamate - DEAE diethylaminoethyl gel (anion exchanger) - DEL diethyllead - DET diethyltin - DMA dimethylarsinic acid - DMGe dimethylgermanium - DMHg dimethylmercury - DML dimethyllead - DMSb dimethylstibinic acid - DMT dimethyltin - DPhT diphenyltin - DPrT dipropyltin - EDTA ethylenediaminetetraacetate - FFF field flow fractionation - GC gas chromatography - HEPES 4-(2-hydroxyethyl)-1-piperazine-ethanesulfonic acid - HPLC high performance liquid chromatography - ICP inductively coupled plasma - IEC ion exchange chromatography - IIC ion interaction chromatography - LC liquid chromatography - MBT monobutyltin - MCyT monocyclohexyltin - MEA monoethylarsinic acid - MEHg monoethylmercury - MEL monoethyllead - MET monoethyltin - MIP microwave induced plasma - MMA monomethylarsonic acid - MMGe monomethylgermanium - MMHg monomethylmercury - MML monomethyllead - MMSb monomethylstibonic acid - MMT monomethyltin - MPhHg monophenylmercury - MPhT monophenyltin - MPrT monopropyltin - MS mass spectrometry - NAA neutron activation analysis - NaBS sodium 1-butanesulfonate - NaDS sodium dodecylsulfonate - NaPS sodium pentanesulfonate - PAGE polyacrylamide gel electrophoresis - PAR 4-(2-pyridylazo)resorcinol - PIXE proton induced X-ray emission - QF quartz furnace - RPC reversed phase partition chromatography - SDS sodium dodecyl sulfate - SEC size exclusion chromatography - SFC supercritical fluid chromatography - TBAP tetrabutylammonium phosphate - TAL tetraalkyllead - TBT tributyltin - TCyT tricyclohexyltin - TeEL tetraethyllead - TEL triethyllead - TeML tetramethyllead - TET triethyltin - TGME thioglycolic methyl ester - THF tetrahydrofuran - TMA trimethylarsinic acid - TMAH tetramethylammonium hydroxide - TMGe trimethylgermanium - TML trimethyllead - TMT trimethyltin - TPhT triphenyltin - TPrT tripropyltin - Tris tris(hydroxymethyl)aminomethane     

3-芳基-5-巯基-1,2,4-三唑的亲核取代反应研究

以3-芳基-5-巯基-1,2,4-三唑为原料合成了20个3-芳基-1,2,4-三唑-5-巯基乙酸乙酯(2a～e)、3-芳基-1,2,4-三唑-5-巯基乙酸(3a～e)、3-芳基-5,6-二氢噻唑并[2,3-c]均三唑(5a～e)和3-芳基-6,7-二氢均三唑并[3,4-b][1,3]噻嗪(6a～e)。研究了3a～e在微波辐射下的环化反应，合成了5个3-芳基-5-氧代-6H-噻唑[2,3-c]均三唑(4a～e)。产物经元素分析、红外、核磁共振以及质谱方法确定了结构。初步研究了代表化合物的生物活性。     

磺酰氨基酸钛配合物对Diels-Alder反应的对映选择性催化作用

研究了对甲苯磺酰基-L-缬氨酸、对甲苯磺酰基-L-苯丙氨酸、对甲苯磺酰基-L-亮氨酸、对甲苯磺酰基-L-异亮氨酸、对甲苯磺酰基-L-脯氨酸、1-萘磺酰基-L-缬氨酸、1-萘磺酰基-L-苯丙氨酸、1-萘磺酰基-L-亮氨酸和1-萘磺酰基-L-异亮氨酸与钛的配合物对环戊二烯与丙烯酸甲酯的环加成反应的对映选择性催化作用。萘磺酰基氨基酸钛配合物的对映选择性比对甲苯磺酰基氨基酸钛配合物好,氨基酸与钛比为2:1时比1:1要好得多。1-萘磺酰基-L-异亮氨酸与钛的2:1配合物的对映选择性最好,e.e.值为56%。     

Struktur und synthese von flavonol-triosiden aus rhamnus-arten

By synthesis and ¹³C-NMR spectroscopic investigations of rhamnocitrin-, rhamnazin- and rhamnetin - 3 - O - [O - α - l - rhamnopyranosyl - (1 → 4) - O - α - l - rhamnopyranosyl - (1 → 6)] β - d - galactopyranosides and of rhamnocitrin - 3 - O - [O - α - l - rhamnopyranosyl - (1 → 3) - O - α - l - rhamnopyranosyl - (1 → 6)] - β - d - galactopyranoside (rhamnocitrin - 3 - O - β - rhamnisoide) it was proved that all naturally occurring flavonoltriosides, so far isolated from different Rhamnus species, contain the sugar-moiety rhamninose. Thus it was shown that catharticin (rhamnocitrin - 3 - O - β - rhamninoside) is identical with alaternin and xanthorhamnin A (rhamnetin - 3 - O - β - rhamninoside) with xanthorhamnin B, whereas xanthorhamnin C is rhamnazin - 3- O - β - rhamninoside. From Rhamnus saxatilis JACQ., ssp. saxat. a new flavonol - acetyl - trioside was isolated and the structure by MS and ¹³C-NMR spectroscopic means elucidated to be the rhamnetin - 3 - O - [O - α - l - rhamnopyranosyl - (1 → 3) - O - (4 - O - acetyl - ) - α - l - rhamnopyranosyl - (1 → 6)] - β - d - galactopyranoside.     

Synthesis and pharmacological effects of optically active 2-[4-(4-benzhydryl-1-piperazinyl)phenyl]-ethyl methyl 1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-3,5-pyridinedicarboxylate hydrochloride

Optically active 2-[4-(4-benzhydryl-1-piperazinyl)phenyl]ethyl methyl 1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-3,5-pyridinedicarboxylate [(S)-(+)-1 and (R)-(-)-1] hydrochlorides were synthesized with high optical purities from (R)-(-)- and (S)-(+)-1,4-dihydro-5-methoxycarbonyl-2,6-dimethyl-4-(3-nitrophenyl)- 3-pyridinecarboxylic acids [(R)-(-)-6 and (S)-(+)-6], which are available from (+/-)-6 by optical resolution using quinidine and cinchonidine, respectively. From pharmacological investigations of (S)-(+)-1 and (R)-(-)-1 such as the antihypertensive effect on spontaneously hypertensive rats and inhibition of [3H]nimodipine binding to rat cardiac membrane homogenate, the active form of 1 was defined to be the (4S)-(+)-enantiomer of 1.     

Synthesis of n4-dialkyl-l-asparagine and n5-dialkyl-l-glutamine derivatives : Application to the synthesis of related peptides

A general and convenient method for the preparation of N⁴-dialkyl-L-asparegine and N⁵-dialkyl-L-glutamine derivatives is described. The applicability of these derivatives in the preparation of related peptides is illustrated by the syntheses of N² - carbobenzoxy - (N⁴ - dimethyl) - L - asparaginyl - (S - benzyl) - L - cysteinyl - L -prolyl - L - leucylglycine amide and N²- carbobenzoxy - (N⁵ - dimethyl) - L - gtutaminyl - L - asparaginyl - (S-benzyl) - L - cysteinyl - L - prolyl - L - leucylglycine amide in satisfactory yields.     

Isolation and synthesis of glutamine and glutarimide derivatives fromCroton humilis

Extract ofCroton humilis L. were shown to contain N - [N - (2 - methylpropanoyl) -l - glutaminoyl] - 2 - phenylethylamine, N - [N - 2R - methylbutanoyl) -l - glutaminoyl] - 2 - phenylethylamine, 2 - [N- (2 - methylpropanoyl)] - N - phenylethylglutarimide and 2 - [N- (2R - methylbutanoyl)] - N - phenylethylglutarimide. Structural proof was based on acid degradation, spectral studies as well as the synthesis of N - [N- (2- methylpropanoyl) -l - glutaminoyl] - 2 - phenylethylamine and 2 - [N - (2 - methylpropanoyl] - N - phenylethylglutarimide.     

3-取代酚酮5位偶联产物的溴氧化成环反应

报道了采用溴氧化3-异丙烯基(艹卓)酚酮和3-肉桂酰基(艹卓)酚酮合成杂环并(艹卓)酮化合物的新方法。3-异丙烯基(艹卓)酚酮5位偶联产物1a～1f和3-肉桂酰基(艹卓)酚酮5位偶联产物3a～3d分别在吡啶介质中与过量溴作用生成5-取代苯偶氮基-7-溴-3-甲基-8-氢环庚并呋喃-8-酮2a～2f和6-取代苯偶氮基-2-苯基-8-溴-4,9-二氢环庚并吡喃-4,9-二酮4a～4d。     

The synthesis of peptides containing purine and pyrimidine derivatives of DL-alanine

The incorporation of the “base-bearing amino acids”, DL - β - (uracil - 1 - yl)alanine 1 (Uala), DL - β - (thymin - 1 - yl)alanine 2 (Tala), DL - β - (cytosin - 1 - yl)alanine 3 (Cala) and DL - β - (adenin - 9 - yl 4 (Aala) into peptides has been studied. The carboxyl group of each of these compounds was protected by the formation of the ethyl ester. The t - butoxycarbonyl (t-BOC) group was suitable for the protection of the α-amino group of 1 but not that of 2, 3 and 4 because of the formation of ring substituted compounds. Peptides containing the amino acids 1–4 and L-serine were synthesised, however, by the mixed anhydride method; uracil, thymine and adenine residues needed no protection, neither did the cytosine residue provided that it was not present in the intermediate which was treated with ethyl chloroformate to produce the mixed anhydride. In this case reaction with the cytosine residue occurred. By these procedures, four protected dipeptides, namely α - N - t - BOC - L - seryl derivatives of 1–4 and three protected tetrapeptides, namely α - N - t - BOC - L - seryl - DL - β - (thymin - 1 - yl)alanyl - L - ethyl ester (t - BOC - Ser - Tala - Ser - Tala - OEt), t - BOC - Ser - Aala - Ser - Aala - OEt and t - BOC - Ser - Uala - Ser - Uala - OEt were obtained. For the protection of the α-amino group of 2 or 3 the formyl group was found to be satisfactory.     

苯并氮杂冠醚的反式结构及性能的理论研究

用分子动力学模拟退火找出苯并氮杂冠醚(C~1~8H~2~3O~7N)的最低能量构型后,用半经验量子化学方法AM1分别优化出了该苯并氮杂冠醚的顺、反式构型,对反式进行了前沿轨道、电荷密度计算,并作了振动分析。优化计算苯并氮杂冠醚反式构型的化合物结构数据与X射线晶体测定结果一致。对其振动分析,指认了化合物不同种类键的振动红外特征吸收峰。结构分析表明这种苯并氮杂冠醚的反式结构呈马蹄铁型,分子内有较大空腔,能够嵌入稀土金属阳离子,有较好的配位性。     

一步法合成取代-1,2-苯醌类化合物

应用固定化多酚氧化酶催化的氧化-迈克尔加成反应,一步合成了4,5-二取代-1,2-苯醌类化合物:4,5-N,N-二(苯胺基)-1,2-苯醌,4,5-N,N-二(对甲苯胺基)-1,2-苯醌,4,5-N,N-二(间氯苯胺基)-1,2-苯醌,4,5-N,N-二(对溴苯胺基)-1,2-苯醌。用化学法(I_2—KI)进行氧化-迈克尔加成反应也成功地合成了4,5-二取代-1,2-苯醌类化合物。应用紫外光谱方法证明了氧化-迈克尔加成反应的机制。     

Higher isoprenoids—VII: A new approach to the degradation of cyclolaudenol side-chain

An efficient new procedure for the degradation of cyclolaudenyl acetate to 3β - acetoxy - 4,4,14α -trimethyl - 9, 19 - cyclo - 5α - pregnan - 20 - one and/or 3β - acetoxy - 4,4,14α - trimethyl - 9,19 - cyclo - 5α -androstan - 17 - one is described. The key-step is simultaneous base-catalysed dehydrohalogenation and isomerisation of the resulting olefin, of a suitably derived halide.     

Investigations on the question of multiple mechanisms in the cope rearrangement

The possible occurrence of the ionic Cope rearrangement, and other non-concerted mechanisms is discussed. The synthesis of 2 - (1 - ethyl - 1 - propenyl) -2- (3 - p - methoxyphenylallyl)malononitrile (1b) and its clean thermal 1,3 rearrangement to (1 - ethyl - 5 - p - methoxyphenyl - 2 - methyl - 4 - pentenylidene)malononitrile (4) are reported. This result contrasts with the rearrangement of 2 - (1,1 - dideuterioallyl) - 2 -(1 - ethyl - 1 - propenyl)malononitrile (1c) which isomerizes cleanly in a 3,3 rearrangement. Rearrangement of 2 - (1 - cyclohexenyl) - 2 - (3 - p - methoxyphenylallyl)malononitrile (11), however, leads sluggishly to [2 - (p - methoxy - α - vinylbenzyl)cyclohexylidene]malononitrile (19) (3,3 shift) and rearrangement of 2 - (1 - isopropyl - 2 - methyl - 1 - propenyl) - 2 -(3 - p - methoxyphenylallyl)malononitrile (12) leads, also slowly, to (1 - isopropyl - 5-p- methoxyphenyl - 2,2 - dimethyl - 4 - pentenylidene)malononitrile (14) (1,3 shift). Rearrangement of 1b in the presence of sodium borohydride allows interception of the proposed ionic intermediates and isolation of 2 - (1 - ethylpropylidene)malononitrile (5) and anethole (21c). Ion trapping experiments also gave positive results in the 3,3 rearrangement of 11. These results are discussed in terms of the ionic Cope rearrangement.     

N-三甲基硅基对甲苯磺酰胺与对甲苯磺酸酯的反应

报道了3-氧杂-1,5-二戊醇二对甲苯磺酸酯及1,4-丁二醇二对甲苯磺酸酯与N-三甲基硅基对甲苯磺酰胺在碱存在下反应分别得到N-对甲苯磺酰基吗啡啉和N-对甲苯磺酰基四氢吡咯这一新的有机硅胺与磺酸酯的反应,在相同条件下N-三甲基硅基-对甲苯磺酰胺与对甲苯磺酸甲酯反应后仅得到N-甲基对甲苯磺酰胺,对此反应提出了可能的反应途径。     

The first enantiomerically pure [n]triangulanes and analogues: sigma-[n]helicenes with remarkable features

(M)-(-)- and (P)-(+)-Trispiro[2.0.0.2.1.1]nonanes [(M)- and (P)-3] as well as (M)-(-)- and (P)-(+)-tetraspiro[2.0.0.0.2.1.1.1]undecanes [(M)- and (P)-4]-enantiomerically pure unbranched [4]- and [5]triangulanes-have been prepared starting from racemic bicyclopropylidenecarboxylic [(1RS)-12] and exo-dispiro[2.0.2.1]heptane-1-carboxylic [(1RS,3SR)-13] acids. The optical resolutions of rac-12 and rac-13 furnished enantiomerically pure acids (S)-(+)-12, (R)-(-)-12, (1R,3S)-(-)-13, and (1S,3R)-(+)-13. The ethyl ester (R)-25 of the acid (R)-(-)-12 was cyclopropanated to give carboxylates (1R,3R)-26 and (1R,3S)-26. The ester (1R,3S)-26 and acids (1R,3S)-13 and (1S,3R)-13 were converted into enantiomerically pure methylene[3]triangulanes (S)-(-)- and (R)-(+)-28. An alternative approach consisted of an enzymatic deracemization of endo-[(1SR,3SR)-dispiro[2.0.2.1]heptyl]methanol (rac-20) or anti-[(1SR,3RS)-4-methylenespiropentyl]methanol (rac-18). This afforded (S)-(-)- and (R)-(+)-28 (starting from rac-20), as well as enantiomerically pure (M)-(-)- and (P)-(+)-1,4-dimethylenespiropentanes [(M)- and (P)-23] starting from rac-18. The methylenetriangulanes (S)-(-)- and (R)-(+)-28 were cyclopropanated furnishing (M)- and (P)-3. The rhodium-catalyzed cycloaddition of ethyl diazoacetate onto (S)-(-)- and (R)-(+)-28 yielded four diastereomeric ethyl trispiro[2.0.0.2.1.1]nonane-1-carboxylates in approximately equal proportions. The enantiomerically pure esters (1R,3S,4S)- and (1S,3R,4R)-30 were isolated by careful distillation and then transformed into [5]triangulanes (M)- and (P)-4 using the same sequence of reactions as applied for (M)- and (P)-3. The structures of the key intermediates (R)-12 and rac-31 were confirmed by X-ray analyses. Although [4]- and [5]triangulanes have no chromophore which would lead to any significant absorption above 200 nm, they have remarkably high specific rotations even at 589 nm with [alpha](20)D=-192.7 [(M)-3, c=1.18, CHCl(3))] or +373.0 [(P)-4, c=1.18, CHCl(3))]. This remarkable optical rotatation is in line with their helical arrangement of sigma bonds, as confirmed by a full valence space single excitation configuration interaction treatment (SCI) in conjunction with DFT computations at the B3LYP/TZVP//B3LYP/6-31+G(d,p) level of theory which reproduce the ORD very well. Thus, it is appropriate to call the helically shaped unbranched [n]triangulanes the "sigma-[n]helicenes", representing the sigma-bond analogues of the aromatic [n]helicenes.     

Synthesis of enantiomerically pure 1,2-diamine derivatives of 7-azabicyclo[2.2.1]heptane. New leads as glycosidase inhibitors and rigid scaffolds for the preparation of peptide analogues

Enantiomerically pure alcohols (-)- and (+)-7-tert-butoxycarbonyl-6-endo-p-toluenesulfonyl-7-azabicyclo[2.2.1]hept-2-en-5-endo-ol ((-)-11 and (+)-11) have been obtained from the Diels-Alder adduct of N-(tert-butoxycarbonyl)pyrroel and 2-bromo-1-p-toluenesulfonylacetylene, including a resolution method. These two alcohols were converted into (+)- and (-)-5-exo-amino-7-(tert-butoxycarbonyl)-2,3-exo-isopropylidenedioxy-7-azabicyclo[2.2.1]heptane ((+)-18 and (-)-18) and (+)- and (-)-5-endo-amino-7-(tert-butoxycarbonyl)-2,3-exo-isopropylidenedioxy-7-azabicyclo[2.2.1]heptane ((+)-19 and (-)-19) after adequate functionalization and desulfonylation steps. The corresponding conformationally constrained bicyclic 1,2-diamines (+)-4, (-)-4, (+/-)-5, (+/-)-6, (+)-7, and (-)-7 were obtained from the protected precursors 18 and 19 and evaluated as glycosidase inhibitors. Diamines (+)-4, (-)-4, (+)-6, and (-)-6 can be seen as new nonpeptide molecular scaffolds for the design of peptide analogues.     

The Williamson Reaction: A New and Efficient Method for the Alternate Resolution of 2,2'-Bis(bromomethyl)-1,1'-binaphthyl and 1,1'-Binaphthalene-2,2'-diol

Treatment of 2,2'-bis(bromomethyl)-1,1'-binaphthyl [(R,S)-2] with 1,1'-binaphthalene-2,2'-diol (+)-(R)-1 and cesium or potassium carbonate in refluxing acetone, gave the diastereoisomeric dioxacyclophanes (-)-(R,S)-3a and (+)-(R,R)-3b, both obtained in high yield, and the cyclic tetraether (+)-(R,R,R,S)-4 as isolated side product. Boron tribomide-promoted ether cleavage of 3a and 3b gave optically pure (-)-(S)-2 and (+)-(R)-2, respectively, and the recovered diol (+)-(R)-1. Alternatively, the same reaction sequence furnished the resolved diols (-)-(S)-1 and (+)-(R)-1 from (R,S)-1 and (+)-(R)-2, as well as optically pure 2,2'-bis(chloromethyl)-1,1'-binaphthyl (+)-(R)-5 from the racemic dibromide (R,S)-2 by using boron trichloride for ether cleavage.