Stereoselective Total Synthesis of Copa and Ylango Sesquiterpenoids: (+)-Copacamphor, (+)-Copaborneol, (+)-Copaisoborneol, (−)-Ylangocamphor, (−)-Ylangoborneol, (−)-Ylangoisoborneol

1975 ◽  
Vol 53 (19) ◽  
pp. 2838-2848 ◽  
Author(s):  
Edward Piers ◽  
Ronald W. Britton ◽  
M. Bert Geraghty ◽  
Robert J. Keziere ◽  
Fusao Kido
Keyword(s):  
Total Synthesis ◽  
Liquid Ammonia ◽  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
High Yield ◽  
Lithium Aluminum ◽  
Alkylation Product ◽  
Intramolecular Alkylation ◽  
Enolate Anion ◽  
Stereoselective Syntheses

Efficient, stereoselective syntheses of the tricyclic sesquiterpenoids (+)-copacamphor (3), (+)-copaborneol (4), (+)-copaisoborneol (5), (−)-ylangocamphor (6), (−)-ylangoborneol (7), and (−)-ylangoisoborneol (8) are described. Conversion of the keto acetate 9 (previously synthesized from the dione 1) into the keto tosylate 17 was accomplished via an eight-step sequence. Intramolecular alkylation of 17 afforded, in high yield, (+)-copacamphor (3), which had previously been converted into the corresponding alcohols 4 and 5 by Kolbe-Haugwitz and Westfelt. Alkylation of the enolate anion of the bicyclic dione 2 with 2-bromopropane in hexamethylphosphoramide gave mainly the O-alkylation product 19. Conversion of 19 into the keto mesylate 29 was carried out in 5 synthetic steps. Intramolecular alkylation of 29 afforded (−)-ylangocamphor (6). Reduction of the latter with calcium in liquid ammonia gave (−)-ylangoborneol (7), while reduction with lithium aluminum hydride yielded (−)-ylangoisoborneol (8).

On the crossed-aldol reaction of cyclohexane-1,2-dione with acetone, and the preparation of pyrroline derivatives from the product

1988 ◽  
Vol 66 (5) ◽  
pp. 1081-1083 ◽  
Author(s):  
George M. Strunz ◽  
Chao-Mei Yu
Keyword(s):  
Potassium Carbonate ◽  
Liquid Ammonia ◽  
Lithium Aluminum Hydride ◽  
Aldol Reaction ◽  
Aluminum Hydride ◽  
Dipole Interaction ◽  
Lithium Aluminum ◽  
Methyl Ketones

Acetone reacts with cyclohexane-1,2-dione, on refluxing in the presence of potassium carbonate, to give the crossed-aldol product, 2-hydroxy-2-acetonylcyclohexanone, 2 (R=CH3). Other methyl ketones react similarly with cyclohexane-1,2-dione. This is believed to be a consequence of unfavorable dipole interaction in the 1,2-dione. The product, on reaction with liquid ammonia, afforded the 5-amino-4-hydroxy-1-pyrroline derivative, 5, which was reduced with lithium aluminum hydride to the 3-hydroxy-1-pyrroline, 7.

Total Synthesis of Several Monodeoxy and Dideoxy-DL-hexopyranoses from 6,8-Dioxabicyclo[3.2.1]oct-2-ene and 6,8-Dioxabicyclo[3.2.1]oct-3-ene

1971 ◽  
Vol 49 (12) ◽  
pp. 2132-2138 ◽  
Author(s):  
T. P. Murray ◽  
U. P. Singh ◽  
R. K. Brown
Keyword(s):  
Hydrochloric Acid ◽  
Total Synthesis ◽  
Dilute Hydrochloric Acid ◽  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Lithium Aluminum ◽  
Osmic Acid ◽  
Aqueous Base

Reaction of osmic acid with 6,8-dioxabicyclo[3.2.1]oct-3-ene (1) gave 1,6-anhydro-4-deoxy-β-DL-ribo-hexopyranose (3, R = H) which was hydrolyzed to 4-deoxy-α,β-DL-ribo-hexopyranose (4, R = H). Conversion of 1 to 1,6:2,3-dianhydro-4-deoxy-β-DL-ribo-hexopyranose (5) followed by treatment of 5 with lithium aluminum hydride, gave 1,6-anhydro-3,4-dideoxy-β-DL-erythro-hexopyranose (6, R = H), and this in turn was hydrolyzed to 3,4-dideoxy-α,β-DL-erythro-hexopyranose (7, R = H).Reaction of osmic acid with 6,8-dioxabicyclo[3.2.1]oct-2-ene (2) gave 1,6-anhydro-2-deoxy-β-DL-riob-hexopyranose (8, R = H), which was hydrolyzed to 2-deoxy-DL-riob-hexopyranose (9, R = H). Compound 2 was converted to 1,6:3,4-dianhydro-2-deoxy-β-DL-ribo-hexopyranose (10) which was hydrolyzed by aqueous base to 1,6-anhydro-2-deoxy-β-DL-arabino-hexopyranose (12) and this in turn was hydrolyzed by dilute hydrochloric acid to 2-deoxy-α,β-DL-arabino-hexopyranose (2-deoxy-DL-glucose) (13). The reaction of 10 with lithium aluminum hydride gave 1,6-anhydro-2,3-dideoxy-β-DL-erythro-hexopy-ranose (14).Yields were good to excellent in each of the above reactions.

scholarly journals A Facile Synthesis of 3-(Chloromethyl)-2-methyl-1,1′-biphenyl

2019 ◽  
Vol 31 (12) ◽  
pp. 3009-3011
Author(s):  
Lele Zhang ◽  
Songbo Cheng ◽  
Hang Hu ◽  
Defeng Xu
Keyword(s):  
High Risk ◽  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
High Yield ◽  
Synthesis Process ◽  
Lithium Aluminum ◽  
Efficient Synthesis ◽  
Facile Synthesis ◽  
Synthetic Process ◽  
Safety Issues

3-(Chloromethyl)-2-methyl-1,1′-biphenyl is a key intermediate for the preparation of bifenthrin, an insecticide which belongs to pyrethroid. The traditional synthetic process of 3-(chloromethyl)-2-methyl- 1,1′-biphenyl is complicated and involves high-toxic and high-risk reagents such as thionyl chloride, lithium aluminum hydride and methyl iodide, which causes significant environmental problems and safety issues. Herein, a facile and efficient synthesis process of 3-(chloromethyl)-2- methyl-1,1′-biphenyl was developed. The synthetic process is shortened from 6 steps to only 4 steps and avoids the use of high-toxic and high-risk reagents. Moreover, 3-(chloromethyl)-2-methyl-1,1′-biphenyl can be obtained by simple purification process in high yield (73.9 %). Compared with the traditional synthetic process, the synthetic process of 3-(chloromethyl)-2-methyl-1,1′-biphenyl reported here is more environmental friendly and efficient.

Total Synthesis of DL-Glucose, 3-O-Methyl-DL-glucose, and 3-Deoxy-DL-ribo-hexopyranose from 1,6:3,4-Dianhydro-β-DL-allo-hexopyranose, a Product Obtained from Acrolein Dimer

1971 ◽  
Vol 49 (20) ◽  
pp. 3342-3347 ◽  
Author(s):  
U. P. Singh ◽  
R. K. Brown
Keyword(s):  
Total Synthesis ◽  
Acid Hydrolysis ◽  
Sodium Methoxide ◽  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Barium Hydroxide ◽  
Lithium Aluminum ◽  
Methyl Glycoside ◽  
Acid Catalyzed ◽  
Hydrolysis Of

The reaction of butyllithium in ether with 1,6:2,3-dianhydro-4-deoxy-β-DL-ribo-hexopyranose (1), a substance obtained in five steps from acrolein dimer, gave 1,6-anhydro-3,4-dideoxy-β-DL-erythro-hex-3-enopyranose (2). The compound 1,6:3,4-dianhydro-β-DL-allo-hexopyranose (3), obtained from 2, was converted by reaction with aqueous barium hydroxide followed by hydrolysis of the product, to DL-glucose 5. Treatment of 3 with sodium methoxide in methanol followed by acid hydrolysis of the 1,6-anhydro intermediate 6, gave 3-O-methyl-DL-glucose (7). The same intermediate, 6, along with the methyl glycoside 8, could be obtained by the acid-catalyzed reaction of 3 with methanol. Lithium aluminum hydride reacted with 3 to form 1,6-anhydro-3-deoxy-β-DL-ribo-hexopyranose (9), which was hydrolyzed readily to 3-deoxy-DL-ribo-hexopyranose (10).Yields were excellent throughout. All products obtained from the oxirane 3 were those resulting only from trans diaxial opening of the oxirane ring.

Notes: 7-Phenyl-2:6:8-trioxaspiro(3,5)-nonane: A High Yield Reduction with Lithium Aluminum Hydride

1959 ◽  
Vol 24 (11) ◽  
pp. 1832-1833 ◽  
Author(s):  
Riyad Nassar ◽  
Costas Issidorides
Keyword(s):  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
High Yield ◽  
Lithium Aluminum ◽  
Yield Reduction

A total synthesis of (±)-triophamine

1984 ◽  
Vol 62 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Edward Piers ◽  
J. Michael Chong ◽  
Kirk Gustafson ◽  
Raymond J. Andersen
Keyword(s):  
Total Synthesis ◽  
Sulfur Trioxide ◽  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Lithium Aluminum ◽  
Yield Reduction ◽  
Diisobutylaluminum Hydride ◽  
H Nmr ◽  
Isomeric Acid ◽  
Nitrophenyl Ester

Treatment of ethyl 2-pentynoate (14) with lithium (phenylthio)(tri-n-butylstannyl)cuprate (12) afforded, in 76% yield, ethyl (Z)-3-(tri-n-butylstannyl)-2-pentenoate (15). On the other hand, when compound 14 was allowed to react with the (tri-n-butylstannyl)copper reagent 13, ethyl (E)-3-(tri-n-butylstannyl)-2-pentenoate (21) was produced in 83% yield. Reduction (diisobutylaluminum hydride, ether) of the esters 15 and 21 gave the alcohols 16 and 22, respectively. Treatment of each of the latter substances with pyridine – sulfur trioxide complex, followed by further reduction of the resultant intermediates with lithium aluminum hydride, provided the geometrically isomeric alkenylstannanes 17 and 23. Conjugate addition of (E)-3-lithio-2-pentene (18) (formed by transmetalation of 17) to compound 19 produced the olefinic trimethylhydrazide 20, which was converted (diisobutylaluminum hydride, ether; pyridinium dichromate, dimethylformamide) into the corresponding carboxylic acid 2. Subjection of compound 23 to a sequence of reactions identical with that used for the conversion of 17 into 2 provided the isomeric acid 3, which was identical (infrared, 1H nmr) with the natural acid derived from triophamine (1). Conversion of 3 into the p-nitrophenyl ester 26, followed by condensation of the latter substance with guanidine, afforded a chromatographically separable mixture of (±)-triophamine (1) and the corresponding diastereomer.

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