Intramolecular cycloalkylation synthesis

Christoph, G. Hoppe, D. Asymmetric synthesis of 2-alkenyl-l-cyclopentanols via Sn-Li exchange and intramolecular cycloalkylation. 

Cycloalkylation (7, 148).2 Cycloalkylation of 2 with (Z)-l was used as one step in a total synthesis of (+ )-sesbanine (6), a constituent of Seshania drummondii seeds with antileukemic activity. The hydroxyl group was introduced into the cyclopentene ring of 4 by iodolactonization followed by reduction to give 5. Final steps included aminolysis of the lactone ring, intramolecular addition of the amide anion to the CN group, and hydrolysis to give 6. 

Multiple intramolecular ring closures of aryl-substituted unsaturated long chain alcohols, acids, acid chlorides and ethers in the presence of Friedel-Crafts catalysts have been extensively employed to synthesize polynuclear hydroaromatic hydrocarbons and polycyclic ketones. This is illustrated by two examples shown in equations (112) and (113). The application of stereospecific cycloalkylations in approaching the synthesis of complex organic molecules has been reviewed by Barclay. ... 

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