Total Synthesis of (+)-Trienomycins A and F

Smith, Amos B.; Barbosa, Joseph; Wong, Weichyun; Wood, John L.

doi:10.1021/ja00148a034

Cited by 29 publications

(18 citation statements)

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“…Thus, CbzNH 2 participated in the twofold aza-Michael addition under Brønsted acid catalysis to give the cis-2,6-disubstituted piperidine 17 (Scheme 4). [29,30] Hydride reductions of trans-15 and cis-17 with Li(t-BuO) 3 BH, Li(s-Bu) 3 BH and LiEt 3 BH gave, following Ndeprotection, useful quantities of three new diastereomers of lythranidine methyl ether 10, namely the 3-epi (18), 3,5-di-epi (19), 5-epi (20) forms, as shown in Scheme 4. The identity of each diastereomer was confirmed by single crystal X-ray analysis.…”

Section: Angewandte Chemiementioning

confidence: 99%

“…[18] Closure of the macrocycle was achieved using an unusual one pot sequence involving the generation of stabilized bisylide 13 and intermolecular-intramolecular double Wittig reaction with 1,5-pentanedial 8. [19] The bis-ylide 13 was generated through a twofold nucleophilic acyl substitution/ deprotonation [20] of diester 12. The optimized one pot process gave a 70:30 mixture of E,E-14 and Z,E-14 macrocycles in 43 % yield.…”

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confidence: 99%

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Five Step Total Synthesis of Lythranidine

2021

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A concise synthesis of the alkaloid lythranidine is reported. The strategy exploits the targets local C 2 symmetry by adopting a two directional synthetic approach, first in an acyclic environment, then in a cyclic system and finally in a bridged macrocyclic domain. The latter phase of the synthesis, which installs all four stereocenters, involves a thermodynamically controlled, twofold intermolecular/transannular aza-Michael addition and a twofold hydride reduction. The synthesis is one third of the length of the most step-economic previous approach, providing access to gram quantities of the natural product. The broad-spectrum nature of the synthesis is demonstrated through the preparation of three diastereomeric analogues of the natural product.

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Section: Angewandte Chemiementioning

confidence: 99%

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confidence: 99%

Five Step Total Synthesis of Lythranidine

2021

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“…Bicyclo[3.1.1]hept‐2‐ene ( 1 ), named “norpinene,” was first established in 1972, well after the C 10 H 16 terpene hydrocarbon α‐pinene had been and still is studied intensively . In 1974, Dietrich and Musso followed two C 7 H 9 D bicyclo[3.1.1]hept‐2‐enes demonstrating a degenerate thermal isomerization (Scheme ) .…”

Section: Introductionmentioning

confidence: 99%

“…Bicyclo[3.1.1]hept-2-ene (1), named "norpinene," was first established in 1972, [1] well after the C 10 H 16 terpene hydrocarbon α-pinene had been and still is studied intensively. [2][3][4][5][6] In 1974, Dietrich and Musso followed two C 7 H 9 D bicyclo[3.1.1]hept-2-enes demonstrating a degenerate thermal isomerization (Scheme 1). [7] Starting with 3-d-1, thermal energy results in evolution toward a 50:50 1-d-1:d-3-1 pair of the two compounds.…”

Section: Introductionmentioning

confidence: 99%

“…[7] Starting with 3-d-1, thermal energy results in evolution toward a 50:50 1-d-1:d-3-1 pair of the two compounds. The degenerate thermal isomerization demonstrated the [1,3] sigmatropic carbon shifts vividly, but a full account of the thermal chemistry of 1 was not developed further. Several more effective syntheses of bicyclo[3.1.1]hept-2-ene have been contributed.…”

Section: Introductionmentioning

confidence: 99%

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Degenerate thermal isomerizations of bicyclo[3.1.1]hept‐2‐ene: strategy and analysis

Baldwin

Hudson

2014

J of Physical Organic Chem

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Bicyclo[3.1.1]hept‐2‐ene was first prepared and well identified in 1972. In 1974, the degenerate thermal isomerization involving 1‐d‐ and 3‐d‐bicyclo[3.1.1]hept‐2‐ene was approached successfully, as one of the two deuterium‐labeled structures was selected, heated, and equilibrated. There has been no further study of this degenerate isomerization. Here, a detailed outline of reaction trajectories for d2‐labeled bicyclo[3.1.1]hept‐2‐enes is given that will establish the four independent kinetic parameters needed for 20 linking paths between six d2‐species. The use of racemates, eliminating chiral separations and dissections, provides degenerate isomerization paths providing this method with general utility. Copyright © 2014 John Wiley & Sons, Ltd.

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Asymmetric Aldol Reactions Using Boron Enolates

1997

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The directed aldol reaction allows the construction of new carbon–carbon bonds in a regio‐, diastereo‐, and enantioselective manner. The kinetically controlled, boron‐mediated aldol reaction is particularly powerful for the efficient synthesis of β‐hydroxy carbonyl compounds. Compared to other metal enolates, the boron–oxygen bond in boron enolates is relatively short which, on addition to aldehydes, leads to tight cyclic transition states and highly stereoselective carbon–carbon bond formation. Moreover, variation of the steric demands of the ligands on boron allows discrimination between competing transition states. Chiral auxiliaries attached to the boron enolate are frequently employed to control the relative and absolute stereochemistry of the aldol products. Asymmetric reactions using chiral ligands on boron are also possible and these produce useful enantiomerically enriched adducts. The utility of boron‐mediated aldol reactions has been demonstrated in numerous total syntheses of complex polyoxygenated natural products, and several of these are highlighted in the Application to Synthesis section of this chapter. Several reviews of the directed aldol reaction are available, including the Organic Reactions chapter by Mukaiyama in 1981. 9 The material covered in this review concerns only the asymmetric formation of β‐hydroxy carbonyl compounds using boron enolates and surveys the literature from 1981 until the end of 1995.

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Total Synthesis of (+)-Trienomycins A and F

Cited by 29 publications

References 0 publications

Five Step Total Synthesis of Lythranidine

Five Step Total Synthesis of Lythranidine

Degenerate thermal isomerizations of bicyclo[3.1.1]hept‐2‐ene: strategy and analysis

Asymmetric Aldol Reactions Using Boron Enolates

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