Carbocycles ring-contracted

Redmore, D. Gutsche, C. D. Carbocyclic Ring Contraction Reactions, in Advances in Alicyclic Chemistry Hart, H. Karabatsos, G. J., Eds. Academic Press New York. 1971 Vol. 3, p 1 -138. 

D. Redmore and C. D. Gutsche, in Carbocyclic Ring Contraction Reactions (Eds H. Hart and... 

Redmore D, Gutsche CD. Carbocyclic ring contraction reactions. In Hart H, Karabastos GJ, editors. Advances in alicyclic chemistry. Vol. 3. New York Academic Press 1971 p 1-138. 

The reaction of cyanogen azide with enamines of cyclic ketones to yield a cyanoamidine with one less member in the carbocyclic ring represents a potentially valuable method of ring contraction under mild conditions (199a). The reaction probably proceeds first by 1,3 cycloaddition of the azide to the enamine followed by rearrangement and elimination of a molecule of nitrogen. 

Medium sized carbocycle synthesis Ring contracting [1,2]-Wittig rearrangement Yadav and Ravishankar have demonstrated that the Wittig rearrangement of the cyclic substrate 32 is useful for the construction of the taxane skeleton 33, albeit in low yield (equation 17). ... 

H. Ito, Y. Motoki, T. Taguchi. and Y. Hanzawa, Zirconium mediated, highly diastereoselective ring contraction of carbohydrate derivatives Synthesis of highly functionalized, enantiomerically pure carbocycles, J. Am. Chem. Soc. 775 8835 (1993). 

Ito, H. et al. Zirconium-Mediated, Highly Diastereoselective Ring Contraction of Carbohydrate Derivatives Synthesis of Highly Functionalized, Enantiomerically Pure Carbocycles. 4.1 1993 [128]... 

The synthesis of cyclopropanes from carbonyl compounds represents a new approach for converting zirconacycles into carbocycles via a deoxygenative ring contraction under Lewis acid activation. It differs in that from the spontaneous Kulinkovich process. Further progress would involve extension to the synthesis of 1,2-substituted cyclopropanes and the development of catalytic and enantioselective variants. 

Degradation Rearrangement Hydrolysis Double bond shift Ring transformation Ring-contraction Ring-expansion Ferrier carbocyclization Anomerization Aromatization Maillard reaction Amadori reaction... 

Xu, Y., Wang, Y., Zhu, S. Reactions of fluoroalkanesulfonyl azides with carbocyclic 3-keto esters structural influence of dicarbonyl substrate on distribution of diazo and ring-contraction products. J. Fluorine Chem. 2000,105, 25-30. 

Scheme 7-35 Synthesis of the parent carbocycle 150 of the NCS chromophore by photolytic ring contraction of the bis-propargylic sulfone 148 (Wender et al.).

In 1982 Funk et al. reported the Ireland-Claisen rearrangement of medium and large ring lactones bearing endocyclic aUyhc alkenes to afford carbocycles (Scheme 4.94) [87]. The rearrangements resulted in a net 4-atom ring contraction... 

Brown s book on organic synthesis via boranes, ° and reviews on sulphene chemistry, the use of activated metals in organic and organometallic chemistry, the Wolff rearrangement of a-diazocarbonyl compounds, and ring contractions and expansions of vicinally disubstituted cyclobutanes and cyclopropylmethyl compoundsare also of appreciable relevance to bridged carbocyclic chemistry. Other pertinent, but more specialized, reviews are recorded in the various sections of this chapter. 

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