Stereoselective synthesis of cis-decalins via Diels–Alder and double Michael addition of substituted Nazarov reagents

Abstract

The base-catalyzed cycloaddition and double Michael cyclization of substituted Nazarov reagents and of l-phenylsulfinyl analogs, with 2-carbomethoxy-2-cyclohexen-I-one 1 yielding cis-decalins is reported. The reaction is highly stereoselective affording cis,cis-or cis,trarls-decalins. Mechanistic aspects are briefly discussed. On dCcrit la cycloaddition catalysCe par des bases des rCactifs de Nazarov substituks, ainsi que d'un analogue 1-phCnylsulfinylC, avec la 2-carbomCthoxy-2-cyclohexenone 1 produisant des cis-dCcalines. La rkaction est hautement stCrCosClective generant des cis,cis-ou cis,trarzs-dCcalines. Les mkcanisrnes de ces reactions sont brikvement discutes. JEAN-FRANCOIS L

Polycyclic Furanobutenolide-Derived Cembranoid and Norcembranoid Natural Products: Biosynthetic Connections and Synthetic Efforts

“…120–122 Addition of the preformed lithium enolate of ethyl acetate ( 376 ) into enone ( R )-330 in 1,2-fashion with sequential 1,3-oxdiative allylic transposition provided ester 377 in 68% yield over two steps. Saponification of ester 377 followed by coupling of the resultant carboxylic acid with 1,3- cis -cyclopentenediol ent -365 and sequential diazotransfer with p -ABSA ( 378 ) afforded α-diazoester ent -363 in 75% yield over three steps.…”

Stereoselective Synthesis of Three Isomers of tert‐Butyl 5‐Hydroxy‐4‐methyl‐3‐oxohexanoate through Alcohol Dehydrogenase‐Catalyzed Dynamic Kinetic Resolution

“…Analytical data were consistent with literature values. [26] tert-Butyl 4-Methyl-3,5-dioxohexanoate (1) Ester 1 was synthesized by acylation of tert-butyl 3-oxopentanoate using Weinreb amide, [8] N-methoxy-N-methylacet-A C H T U N G T R E N N U N G amide, in accordance with the literature method. [5] tert-Butyl 5-Hydroxy-4-methyl-3-oxohexanoate (syn/ anti-rac-2) NaH (416 mg, 60% in petroleum, 10.4 mmol) was suspended in THF (40 mL) and chilled on ice.…”

Functionalized hydrocarbons with condensed ring skeletons. XIV. A dioxotricyclo[8.4.0.02,7]tetradec-6-ene

“…Highly stereoselective syntheses of cis,cis-decalins via a base-catalyzed [2 + 4] cycloaddition of substituted Nazarof reagents were recently reported (Lavall6e, Spino, Ruel, Hogan & Deslongchamps, 1992). The present X-ray structure determination is part of the discussion of the mechanistic aspect of these reactions.…”