Lithium iodide-Boron trifluoride

Diphenylphosphine)lithium, 126 Nickel boride, 197 Samarium(II) iodide, 270 to 1,2-disubstituted compounds B-3-Pinanyl-9-borabicyclo-[3.3.1]nonane, 249 Titanium(III) chloride, 302 of phosphorus compounds Lithium aluminum hydride-Cerium(III) chloride, 159 of sulfoxides and sulfones Sodium iodide-Boron trifluoride ether-ate, 282... 

Triphenylphosphine-Diethyl azodi-carboxylate-Lithium halides, 332 by bromide Sodium bromide, 46 Tetraethylammonium bromide, 46 Triphenylphosphine-Diethyl azodi-carboxylate-Lithium halides, 332 by iodide Sodium iodide, 46 Sodium iodide-Boron trifluoride etherate, 282... 

Perfluorohexyl-l,2-dihydroquinoline (268) was obtained in 72 % yield together with trace amounts of 2-(periluorohexyl)quinoline (269), the latter being formed by the autoxidation of 268. The perfluoroalkylation was improved up to 90 % yield by using 2 equiv. each of pertluorohexyl iodide, boron trifluoride, and methyllithium-lithium bromide. The autoxidation of dihydroquinoline 268 was complete in chloroform after 2 days and 269 was obtained quantitatively [160] (Scheme 79). 

When the metallic additive to the intermediate 374 was zinc dihalide (or another Lewis acid, such as aluminum trichloride, iron trichloride or boron trifluoride), a conjugate addition to electrophilic olefins affords 381 . In the case of the lithium-zinc transmetallation, a palladium-catalyzed Negishi cross-coupling reaction with aryl bromides or iodides allowed the preparation of arylated componnds 384 ° in 26-77% yield. In addition, a Sn2 allylation of the mentioned zinc intermediates with reagents of type R CH=CHCH(R )X (X = chlorine, bromine) gave the corresponding compounds 385 in 52-68% yield. ... 

ESTERS Sodium benzeneselenolate. ETHERS Boron tribromide-Sodium iodide-15-Crown-5. Boron trifluoride etherate. Ferric chloride-Silica. Lithium iodide. Silicon(IV) chloride-Sodiuiu iodide. Sodium iodide-Pivaloyl chloride. 2,4,4,6-Tetrabromocyclohexadiene. Trichloro(methyl)silane. 

Ring opening of tetrahydrofuran derivatives has been studied using chlorotrimethylsilane and sodium iodide 2-methyltetrahydrofuran is opened predominantly to give 5-iodopentan-2-ol but the reaction involving 3-methyltetrahy-drofuran is less selective. Lithium 4,4-di-/-butylbiphenylide has also been used to cause the ring opening of tetrahydrofuran at 80 C in the presence of boron trifluoride etherate. 

Mcthoxyoxazaphosphorinane 20 reacts with aldehydes in a tetrahydrofuran solution at — 78 C in the presence of lithium iodide and boron trifluoride-diethyl ether complex, followed by treatment with aqueous sodium hydroxide, to give diastereomeric a-hydroxy oxazaphospho-rinanes 21 in good yields but with low stereoselectivity [d.r. (21 a/21 b) from 52 48 to 70 30]65. 

Redactiaa of at-luMteUmes Treatment of x-bromoketones with lithium iodide and boron trifluoride in ether or THF at room temperature affords the parent ketone in high yield. The hydrogen was eventually found to originate, presumably as water, in the lithium iodide (Alfa Inorganics, anhydrous ). Only one exception to the reduction was observed, namely a-bromocamphor failed to react. The procedure is also effective for some x-chloroketones (phenacyl chloride, 2-chloropentanone), but fail.s for hindered chloroketones (oi-chloronorbomanone). 

Oppolzer has developed a method of asymmetric synthesis based on the use of the chiral auxiliaries 39A and 39B derived respectively from (+ )-camphor [(+ )-40] and (- )-camphor [(- )-40]. Crotonylation of 39A gave the ester that was attacked by 4-methyl-3-pentenyllithium in the presence of copper iodide tributylphosphine and boron trifluoride from only one side of the molecule, the product 41 having the (S)-configuration (enantioselectivity 98.5%). The ester 42—similarly obtainable from 39B—was methylated under similar conditions, also yielding 41 with 92% enantioselectivity. (S)-Citronellic acid [(S)-36] or (S)-citronellol [(S)-33] were then obtained from 41 by the action of sodium hydroxide or lithium aluminum hydride (Scheme 6). Reduction of potassium... 

Aliphatic ethers are cleaved by acetic anhydride containing boron trifluoride etherate plus lithium iodide at 20° 22 the alcoholic parents of the ether are obtained as main products, together with small amounts of olefin for instance, cyclohexyl acetate and 3/S-cholestanyl acetate are formed from alkoxycyclohexanes and 3/S-alkoxycholestanes, respectively. 

Diphenylcyclopropane has been prepared previously by (1) the Simmons-Smith procedure (24% yield)9 3 19 and modified versions of this method (up to 72%),20 (2) sulfonium ylide addition to 1,1-diphenylethene (61% yield),21 (3) reduction of 1,1-diphenyl-2,2-dihalocyclopropanes with sodium in ammonia (47% yield),22 with sodium and tert-butyl alcohol (80%),6 or with diethyl llthiomethanephosphonate (62%),23 (4) base-promoted cyclization of trimethyl(3,3-diphenylpropyl)ammonium iodide (78%),24 (5) boron trifluoride-promoted cyclization of a corresponding 3-hydroxypropylstannane (97%),25 (6) reaction of 3,3-diphenylpropenoic acid with lithium aluminum hydride (62%),26 (7) reaction of... 

Esters 106 (R = Me, Et or Pr = Et, Pr, r-Bu or PhCHi) of aliphatic carboxylic acids react with lithium acetylides 107 (R = H, C5 Hi i or Ph) in the presence of boron trifluoride etherate in THE to give acetylenic ketones 108 (equation 18). Palladium-[tetrakis(triphenylphosphine)]-copper(I) iodide catalyses the oxidative addition-decarboxylation of propargyl methyl carbonates, e.g. 109, with terminal alkynes to yield 1,2-dien-4-ynes (allenylacetylenes) 110. The regiochemistry of the palladium-catalyzed addition of phenylacetylene to the allenic ester 111 depends on the nature of the catalyst used palladium(III) acetate-triphenylphosphine yields a 81 19 mixture of adducts 112 and 113, while in the presence of tetrakis(carbomethoxy)palladacyclopentadiene-tris(2,4,6-trimethoxyphenyl)phosphine the ratio is reversed to 9 91 k... 

The difficultly accessible trans-syn-trans arrangement of the a-b-c ring system present in steroidal antibiotics has now been synthesized. The known enedione (39) was converted into a 6 1 mixture of the desired compound (40) and its isomer (41) by ketalization of the saturated carbonyl, followed by lithium-ammonia reduction and enolate trapping with methyl iodide. After separation, (40) was converted into the tricyclic enedione (42) by standard procedures. The transfused AB-system was then obtained by ketalization, peracid treatment, and boron trifluoride rearrangement of the resulting epoxide to the keto-diketal (43). Removal of the 6-keto-group was performed under mild conditions by a new... 

Related Reagents. Lithium Aluminum Hydride-(2,2 -Bipy-ridyl)(l,5-cyclooctadiene)nickel Lithium Aluminum Hydride-Bis(cyclopentadienyl)nickel Lithium Aluminum Hydride-Boron Trifluoride Etherate Lithium Aluminum Hydride-Cerium(III) Chloride Lithium Aluminum Hydride-2,2 -Dihydroxy-l, E-binaphthyl Lithium Aluminum Hydride-Chromium(III) Chloride Lithium Aluminum Hydride-Cobalt(II) Chloride Lithium Aluminum Hydride-Copper(I) Iodide Lithium Aluminum Hydride-Diphosphoms Tetraiodide Lithium Aluminum Hydride-Nickel(II) Chloride Lithium Aluminum Hydride-Titanium(IV) Chloride Titanium(III) Chloride-Lithium Aluminum Hydride. 

The preparation of 1-bromo-l-chloro-l-fluoroacetone has been de-scribed. The combination of lithium iodide and boron trifluoride etherate provides a mild, high-yield process for the reductive deiodination of iodoketones. aa -Dibromoketones react with 1,3-dienes in the presence of iron carbonyls to give troponoid compounds (Scheme 96). 

Lithium tetrafluoroborate in wet acetonitrile has been described as an effective combination for the hydrolysis of acetals under mild weakly acidic conditions. Dithians were unaffected. Methods for the hydrolysis of thioacetals continue to appear. Reagents that have been described include a polystyryl-mercury(n) trifluoroacetate combination, which retains the metal on the resin, lead(iv) dioxide and boron trifluoride etherate, aqueous hydrochloric acid in dioxan containing dimethyl sulphoxide, methyl-bis(methylthio)sulphonium hexa-chloroantimonate, and iodoxybenzene, catalysed by toluene-p-sulphonic acid. Dithioacetals derived from ethane-1,2-dithiol may be cleaved with dimethyl sulphoxide in combination with either t-butyl or trimethylsilyl bromides and iodides. Regeneration of ketones from ethanediyl-S S -acetals via the lithium-di-isopropylamide-promoted fragmentation to the thioketone and subsequent hydrolytic work-up only gives satisfactory yields for aryl methylketone derivatives. Dithioacetal SS-dioxides are rapidly cleaved in hot methanolic hydrochloric acid solution. ... 

---