Medium-Sized Rings versus Macrocycles through Rhodium-Catalyzed Ring-Expansion Reactions of Cyclic Acetals

2012 ◽  
Vol 18 (21) ◽  
pp. 6626-6631 ◽  
Author(s):  
Rafael Ballesteros-Garrido ◽  
Diane Rix ◽  
Céline Besnard ◽  
Jérôme Lacour
Keyword(s):  
Ring Expansion ◽  
Cyclic Acetals

Polycyclic oxonium ylides — Use of cyclic acetals as convenient scaffolds in the construction of fused bicyclic compounds containing a medium ring

2006 ◽  
Vol 84 (10) ◽  
pp. 1470-1486 ◽  
Author(s):  
Graham K Murphy ◽  
Fredrik P Marmsäter ◽  
F G West
Keyword(s):  
Ring Expansion ◽  
Major Product ◽  
Side Chains ◽  
Cyclic Acetals ◽  
Bicyclic Compounds ◽  
Oxonium Ylides ◽  
Sulfonium Ylide ◽  
Oxonium Ylide ◽  
Medium Ring

Cyclic mixed acetals with pendant diazoketone side chains undergo efficient rearrangement to ether-bridged cyclooctanoid and cycloheptanoid systems upon treatment with Cu(hfacac)2. Stevens [1,2]-shift of an oxonium ylide furnishes the major product, in some cases accompanied by minor amounts of a product resulting from [1,2]-shift of a sulfonium ylide. These results demonstrate that hetero-substituted carbons are suitable migrating groups for the Stevens [1,2]-shift of oxonium ylides. In cases employing a mixed thioacetal, the resulting sulfide served as a trigger for cleavage of the bridging ether through one of two complementary strategies. In the hydrazulene series, the desired bicyclo[5.3.0]heptene was accompanied by the product of novel transannular SN2′ attack on the resulting allylic ketal.Key words: [1,2]-shift, diazo, medium-sized ring, oxonium ylide, ring expansion.

ChemInform Abstract: Medium-Sized Rings versus Macrocycles Through Rhodium-Catalyzed Ring-Expansion Reactions of Cyclic Acetals.

ChemInform ◽  
2012 ◽  
Vol 43 (38) ◽  
pp. no-no
Author(s):  
Rafael Ballesteros-Garrido ◽  
Diane Rix ◽  
Celine Besnard ◽  
Jerome Lacour
Keyword(s):  
Ring Expansion ◽  
Cyclic Acetals
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