Acid-Catalyzed Cyclization of Vinylsilanes Bearing a Hydroxy Group:  A New Method for Stereoselective Synthesis of Disubstituted Tetrahydrofurans1

2000 ◽  
Vol 122 (46) ◽  
pp. 11348-11357 ◽  
Author(s):  
Katsukiyo Miura ◽  
Shigeo Okajima ◽  
Takeshi Hondo ◽  
Takahiro Nakagawa ◽  
Tatsuyuki Takahashi ◽  
...  
Keyword(s):  
Hydroxy Group ◽  
Stereoselective Synthesis ◽  
New Method ◽  
Group A ◽  
Acid Catalyzed

A stereoselective synthesis of digitoxin. On cardioactive steroids. XIII

1984 ◽  
Vol 62 (7) ◽  
pp. 1403-1405 ◽  
Author(s):  
Thomas Y. R. Tsai ◽  
Haolun Jin ◽  
Karel Wiesner
Keyword(s):  
Stereoselective Synthesis ◽  
New Method ◽  
Cardioactive Steroids ◽  
Acid Catalyzed

The first highly stereoselective synthesis of digitoxin is described. The furyl derivative of digitoxigenin was coupled with one unit of digitoxose using our previously described acid catalyzed method. For the second and third glycosylation a new method involving ethyl thioglycosides and 1,3-participation by a p-methoxy benzoate group was developed. As the final step after deprotection of the triglycoside, the 17-furyl group in the steroid aglycone was converted to a butenolide by our oxidative method.

A NEW METHOD FOR THE STEREOSELECTIVE SYNTHESIS OF NUCLEOSIDES FROM ACYCLIC EPOXY ALDEHYDES

1984 ◽  
Vol 13 (7) ◽  
pp. 1093-1096 ◽  
Author(s):  
Tetsuo Miwa ◽  
Koichi Narasaka ◽  
Teruaki Mukaiyama
Keyword(s):  
Stereoselective Synthesis ◽  
New Method

Stereoselective Synthesis of C-Ketosides by Lewis Acid Catalyzed C-Glycosylation of Alkynyl-Ketoses.

ChemInform ◽  
2003 ◽  
Vol 34 (14) ◽  
Author(s):  
Ana M. Gomez ◽  
Clara Uriel ◽  
Serafin Valverde ◽  
Slawomir Jarosz ◽  
J. Cristobal Lopez
Keyword(s):  
Lewis Acid ◽  
Stereoselective Synthesis ◽  
Acid Catalyzed

Acid-catalyzed reaction of phenols with N-(4,4-diethoxybutyl)sulfonamides – a new method for the synthesis of 2-aryl-1-sulfonylpyrrolidines

2017 ◽  
Vol 53 (2) ◽  
pp. 161-166 ◽  
Author(s):  
Andrey V. Smolobochkin ◽  
Almir S. Gazizov ◽  
Ekaterina A. Anikina ◽  
Alexander R. Burilov ◽  
Michael A. Pudovik
Keyword(s):  
New Method ◽  
Acid Catalyzed

Counterion effects in the catalytic stereoselective synthesis of 2,3′-pyrrolidinyl spirooxindoles

2014 ◽  
Vol 50 (40) ◽  
pp. 5242-5244 ◽  
Author(s):  
Jacob P. MacDonald ◽  
Benjamin H. Shupe ◽  
John D. Schreiber ◽  
Annaliese K. Franz
Keyword(s):  
Lewis Acid ◽  
Stereoselective Synthesis ◽  
Acid Catalyzed

A Lewis acid-catalyzed stereoselective [3+2] annulation of crotylsilanes with iminooxindoles is reported to access 2,3′-pyrrolidinyl spirooxindoles with four stereocenters.

Kinetics and Mechanisms for the Isomerization of Internucleosidic 3'-O-P-CH2-5' and 3'-O-P-CH(OH)-5' Linkages to Their 2',5'-Counterparts

2006 ◽  
Vol 71 (6) ◽  
pp. 859-870 ◽  
Author(s):  
Tuomas Lönnberg ◽  
Šárka Králíková ◽  
Ivan Rosenberg ◽  
Harri Lönnberg
Keyword(s):  
Hydrogen Bond ◽  
Hydroxy Group ◽  
Phosphorus Atom ◽  
Hydrolytic Stability ◽  
Model Compounds ◽  
Hydroxide Ion ◽  
Wide Ph Range ◽  
Acid Catalyzed ◽  
Ph Range

Isomerization of internucleosidic 3'-O-P-CH2-5' and 3'-O-P-CH(OH)-5' phosphonate linkages to their 2',5'-counterparts has been studied over a wide pH-range. The model compounds employed are phosphonate analogs of adenylyl-(3',5')-adenosine and adenylyl-(2',5')-adenosine having either adenosine ((R,S)-1, (R,S)-2) or 5'-deoxyadenosine (3, 4) bonded to the phosphorus atom through the C5'-atom. For comparative purposes, the hydrolytic stability of C5'-hydroxyphosphonate analogs derived from 2'-deoxyadenosine ((R,S)-5) has also been studied. In addition to the expected acid-catalyzed (pH < 3) and pH-independent reactions (pH 3-9), the diastereomeric C5'-hydroxyphosphonate analogs ((R,S)-1, (R,S)-2), but not their deoxy counterparts (3, 4), have been observed to undergo a hydroxide-ion-catalyzed isomerization around pH 11 (90 °C). Evidently a hydrogen bond between the dianionic phosphorane and the C5'-hydroxy group stabilize the phosphorane to such an extent that isomerization via kinetically invisible protonation to monoanion becomes possible. The mechanisms of the isomerization reactions taking place under various conditions are discussed.

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