Effect of allylic substituents on the face selectivity of Diels-Alder reactions of semicyclic dienes

Datta, Sourav; Franck, Richard W.; Tripathy, Rabindranath; Quigley, Gary J.; Huang, Lele; Chen, S.; Sihaed, A.

doi:10.1021/ja00179a036

Cited by 46 publications

(18 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Precedent work by Frank [38] and Larsen [39] had shown that the stereochemical course of Diels-Alder reactions with chiral vinylcyclohexenes bearing an allylic oxygenated substituent at C-3 was governed also by steric factors involving the size of the allylic substituents. As shown in Figure 3 (A [38] and B [39] ) the models proposed by these authors to justify the major or exclusive formation of the anti cycloadducts, corresponded to the preferred endo approach of the dienophile from the face of the diene anti to the oxygenated function.…”

Section: Resultsmentioning

confidence: 99%

Asymmetric Synthesis of Rubiginones A₂ and C₂ and Their 11‐Methoxy Regioisomers

Carreño

Somoza

Ribagorda

et al. 2007

Chemistry A European J

View full text Add to dashboard Cite

Convergent enantioselective syntheses of angucyclinone-type natural products rubiginones A(2) (2) and C(2) (1) and their 11-methoxy regioisomers 3 a and 3 b have been achieved by using two domino processes from a common enantiomerically pure 1-vinylcyclohexene 4. Key steps in the synthesis of this diene were the stereoselective conjugate addition of AlMe(3) on (SS)-[(p-tolylsulfinyl)methyl]-p-quinol (9) and the elimination of the beta-hydroxy sulfoxide fragment, after oxidation to sulfone, to recover a carbonyl group. The first domino sequence comprised Diels-Alder reaction with a sulfinyl naphthoquinone followed by sulfoxide elimination. An efficient opposite regioselection in the cycloaddition step was achieved in the convergent construction of the tetracyclic skeleton using a sulfoxide at C-2 or C-3 of the dienophiles 5 or 6, derived from 5-methoxy-1,4-naphthoquinone. The second domino process, triggered by oxygen and sunlight, allowed the transformation of the initial tetracyclic adducts into the final products after B ring aromatization, silyl deprotection and C-1 oxidation.

show abstract

Section: Resultsmentioning

confidence: 99%

Asymmetric Synthesis of Rubiginones A₂ and C₂ and Their 11‐Methoxy Regioisomers

Carreño

Somoza

Ribagorda

et al. 2007

Chemistry A European J

View full text Add to dashboard Cite

show abstract

“…The π‐facial approach on both diene and dienophile was dictating the stereochemistry at C‐12b, which must result from a double asymmetric induction process. Precedent work by Frank38 and Larsen39 had shown that the stereochemical course of Diels–Alder reactions with chiral vinylcyclohexenes bearing an allylic oxygenated substituent at C‐3 was governed also by steric factors involving the size of the allylic substituents. As shown in Figure 3 ( A 38 and B 39) the models proposed by these authors to justify the major or exclusive formation of the anti cycloadducts, corresponded to the preferred endo approach of the dienophile from the face of the diene anti to the oxygenated function.…”

Section: Resultsmentioning

confidence: 99%

OC022: Quality control in the measurement of nuchal translucency in the first trimester of pregnancy

Brogan¹,

Crossley²,

Stenhouse³

et al. 2003

Ultrasound Obstet Gynecol

View full text Add to dashboard Cite

Convergent enantioselective syntheses of angucyclinone‐type natural products rubiginones A2 (2) and C2 (1) and their 11‐methoxy regioisomers 3 a and 3 b have been achieved by using two domino processes from a common enantiomerically pure 1‐vinylcyclohexene 4. Key steps in the synthesis of this diene were the stereoselective conjugate addition of AlMe3 on (SS)‐[(p‐tolylsulfinyl)methyl]‐p‐quinol (9) and the elimination of the β‐hydroxy sulfoxide fragment, after oxidation to sulfone, to recover a carbonyl group. The first domino sequence comprised Diels–Alder reaction with a sulfinyl naphthoquinone followed by sulfoxide elimination. An efficient opposite regioselection in the cycloaddition step was achieved in the convergent construction of the tetracyclic skeleton using a sulfoxide at C‐2 or C‐3 of the dienophiles 5 or 6, derived from 5‐methoxy‐1,4‐naphthoquinone. The second domino process, triggered by oxygen and sunlight, allowed the transformation of the initial tetracyclic adducts into the final products after B ring aromatization, silyl deprotection and C‐1 oxidation.

show abstract

“…The acetyl group is also twisted out of the plane of ring B; torsion angle C3--C4---Cll---O3 is -22.1 (2) °. A search of the Cambridge Structural Database (Allen, Kennard & Taylor, 1983) revealed several structures with the same three-ring system (Magnus, Walker, Jenkins & Menear, 1986;Datta, Franck, Tripathy, Quigley, Huang, Chen& Sihaed, 1990), but none with two double bonds in ring B. Four structures had one double bond in ring B in the equivalent position of C5==C8c.…”

Section: Commentmentioning

confidence: 99%