Robinson annulation synthesizing compound using

Show syntheses of these compounds using the Robinson annulation reaction ... 

Show how you would use Robinson annulations to synthesize the following compounds. Work backward, remembering that the cyclohexenone is the new ring and that the double bond of the cyclohexenone is formed by the aldol with dehydration. Take apart the double bond, then see what structures the Michael donor and acceptor must have. 

Show how you would use the Robinson annulation to synthesize the following compounds. 

When you need to synthesize a p-hydroxy ketone or aldehyde or an a,p-unsaturated ketone or aldehyde, use an aldol reaction. When you need to synthesize a p-diketone or p-keto ester, use a Claisen reaction. When you need to synthesize a 1,5-dicarbonyl compound, use a Michael reaction. The Robinson annulation is used to synthesize polycyclic molecules by a combination of a Michael reaction with an aldol condensation. 

Example What starting materials are needed to synthesize the following compound using a Robinson annulation ... 

Show the starting materials that you could use to synthesize the following compounds by Robinson annulation. 

Total syntheses of diterpenoid hydrokempenones have been accomplished by Paquette et al.,f using the Pd-catalyzed [3 + 2] cycloaddition methodology. One example is outlined on Scheme 43 and describes the synthesis of an isomeric compound 208 of 3/3-hydroxy-7/3-kemp-8(9)-en-6-one, a defense secretion agent of the neotropical species Nasutitermes octopilis. 3-AUcoxy-2-cyclohexenone 204 was efficiently functionalized and transformed to bicylic adduct 205 via a Robinson annulation reaction. Reduction of the double bond followed by condensation of dimethyl carbonate and oxidation gave the keto ester 206, which was treated with [2-(acetoxymethyl)-3-allyl]trimethylsilane, palladium acetate, and triisopropyl phosphite in refluxing tetrahydrofuran to afford a 98% yield of 207. Substituted methylenecyclopentane 207 was then functionalized by stereoselective reduction and protections, and final closure was done under basic conditions after an ozonolysis step. A modified Barton-McCombie reaction produced the desired tetracyclic adduct 208. 

How To Synthesize a Compound Using the Aldol Reaction 921 How To Synthesize a Compound Using the Robinson Annulation 939... 

The Robinson annulation is used to prepare cyclohexenones. The enone is disconnected to a 1,5-dicarbonyl compound, which is synthesized using an enone and an enolate (either of a p-dicarbonyl compound or an enamine). It is a one-pot process. 

Propose syntheses of the foUowing compounds by using Michael additions followed by aldol condensations (i.e., Robinson annula-tions). Each of the compounds shown has been instrumental in one or more total syntheses of steroidal hormones. (Hint Identify and unravel the cyclohexenone ring in a reverse annulation sequence.)... 

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