THE REDUCTIVE CLEAVAGE OF 1,3-OXATHIOLANES WITH LITHIUM ALUMINUM HYDRIDE IN THE PRESENCE OF ALUMINUM CHLORIDE OR BORON TRIFLUORIDE

1963 ◽  
Vol 41 (10) ◽  
pp. 2671-2682 ◽  
Author(s):  
B. E. Leggetter ◽  
R. K. Brown
Keyword(s):  
Aluminum Chloride ◽  
Lewis Acids ◽  
Chloride Solution ◽  
Boron Trifluoride ◽  
Lithium Aluminum Hydride ◽  
Methylene Chloride ◽  
Aluminum Hydride ◽  
Lithium Aluminum ◽  
Methylene Chloride Solution ◽  
Ether Solution

A number of 1,3-oxathiolanes and 1,3-dithiolanes were subjected to reduction in ether solution by lithium aluminum hydride in the presence of either aluminum chloride or boron trifluoride. Both of these Lewis acids not only isomerized 1,3-oxathiolanes but also catalyzed their hydrogenolysis to the hydroxy thioethers. Under the same conditions neither aluminum chloride nor boron trifluoride had any effect upon 1,3-dithiolanes. However, in methylene chloride solution, 1,3-dithiolanes are isomerized by both Lewis acids although their hydrogenolysis was not achieved, probably due to the insolubility of the hydride in methylene chloride.A mechanistic interpretation is discussed to explain the results obtained.

ANOMALOUS RING CLEAVAGE DURING LITHIUM ALUMINUM HYDRIDE – ALUMINUM CHLORIDE REDUCTION OF 2,2,4,4-TETRAALKYLATED-1,3-DIOXOLANES

1964 ◽  
Vol 42 (5) ◽  
pp. 1005-1008 ◽  
Author(s):  
B. E. Leggetter ◽  
R. K. Brown
Keyword(s):  
Aluminum Chloride ◽  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Reductive Cleavage ◽  
Ring Cleavage ◽  
Lithium Aluminum ◽  
Ether Solution

The anomalous reductive cleavage by LiAlH4–AlCl3 of 2,2,4,4-tetramethyl-1,3-dioxolane in ether solution has been examined. Evidence supports the view that this unexpected direction of ring cleavage is due to steric repression of the formation of the intermediate oxocarbonium leading to cleavage of the C2—O1 bond of the dioxolane ring.

Chemistry of metal hydrides. VII. An iridium(III) carbonyl cation and the formation of iridium(III) hydridocarbonyls

1970 ◽  
Vol 48 (1) ◽  
pp. 119-123 ◽  
Author(s):  
H. C. Clark ◽  
R. K. Mittal
Keyword(s):  
Carbon Monoxide ◽  
Potassium Chloride ◽  
Chloride Solution ◽  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Metal Hydrides ◽  
Lithium Aluminum ◽  
Potassium Chloride Solution

IrCl3(PEt3)3 is readily converted to IrHCl2(CO)(PEt3)2 by treatment with carbon monoxide in hot acetone, ethanol, or 2-methoxyethanol. Perchlorate, tetrafluoroborate, and tetraphenylborate salts containing the [IrCl2(CO)(PEt3)3]+ cation have been prepared, but attempts to obtain salts containing the [IrHCl(CO)(PEt3)3]+ cation give only the neutral hydride, IrHCl2(CO)(PEt3)2. The reactions of [IrCl2(CO)(PEt3)3]+ with ethanol, water, lithium aluminum hydride, aqueous potassium chloride solution, and sodium alkoxides are described.

scholarly journals Pyranosiduloses. II. The synthesis and properties of some alkyl 2,3-dideoxy-2-enopyranosid-4-uloses

1970 ◽  
Vol 48 (18) ◽  
pp. 2877-2884 ◽  
Author(s):  
Bert Fraser–Reid ◽  
Angus McLean ◽  
E. W. Usherwood ◽  
Mark Yunker
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Double Bond ◽  
Magnetic Resonance ◽  
Boron Trifluoride ◽  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Lithium Aluminum ◽  
Crystalline Substance ◽  
Unsaturated Ketones ◽  
Olefinic Double Bond

Ethyl 2,3-dideoxy-α-D-erythro-hex-2-enopyranoside (9a) an accessible and highly crystalline substance is selectively oxidized at the allylic position to ethyl 2,3-dideoxy-α-D-glycero-hex-2-enopyranosid-4-ulose (10a) in 80% yield. This hydroxyketone can be benzoylated, acetylated, and tosylated, and the resulting esters are all highly crystalline, as is the parent ketone. 3,4-Di-O-acetyl-D-xylal reacts with ethanol under boron trifluoride catalysis to give the anomeric mixture of ethyl 4-O-acetyl 2,3-dideoxy-D-glycero-pent-2-enopyranosides which may be separated after deacetylation. The deacetylated α-D anomer (14α) is readily oxidized by manganese dioxide to give an ethyl 2,3-dideoxy pent-2-enopyranosid-4-ulose (6-ethoxy-2,6-dihydropyran-3-one) (12); however, the corresponding β-D (14β) anomer resists oxidation. All of these ketones display a diagnostic nuclear magnetic resonance pattern consisting of clean doublets for H-1 and -3, and a doublet of doublets for H-2. Reduction of 10a with lithium aluminum hydride gives back the parent D-erythro alcohol exclusively, and catalytic hydrogenation saturates the olefinic double bond. These α,β-unsaturated ketones (10) in the hexose series are all levorotatory although their parent D-erythro alcohols (9) are strongly dextrorotatory; the saturated ketones derived from them are also strongly dextrorotatory. The epimeric D-threo alcohols which should also be oxidizable to 10 are however strongly levorotatory.

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