A stereospecific synthesis of napelline

SETHI, S. P.; Atwal, Karnail S.; Marini-Bettolo, R.; Tsai, T. Y. R.; Wiesner, K.

doi:10.1139/v80-298

Cited by 41 publications

(22 citation statements)

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“…The C 20 -diterpenoid alkaloids have also served as classic targets in natural product synthesis, resulting in the total syntheses of natural products within the atisine (1), [13][14][15][16][17][18] veatchine (5), [19][20][21][22][23] and napelline (6) [24,25] subclasses. Despite this progress, synthetic efforts toward the hetisine subclass (4) have been comparatively sparse.…”

Section: Introductionmentioning

confidence: 99%

Asymmetric Synthetic Access to the Hetisine Alkaloids: Total Synthesis of (+)‐Nominine

Peese

Gin

2008

Chemistry A European J

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A dual cycloaddition strategy for the synthesis of the hetisine alkaloids has been developed, illustrated by a concise asymmetric total synthesis of (+)-nominine (7). The approach relies on an early-stage intramolecular 1,3-dipolar cycloaddition of a 4-oxido-isoquinolinium betaine dipole with an enenitrile dipolarophile. Subsequent late-stage pyrrolidine-induced dienamine isomerization/DielsAlder cascade allows for rapid construction of the carbon-nitrogen polycyclic skeleton within this class of C 20 -diterpenoid alkaloids.

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Section: Introductionmentioning

confidence: 99%

Asymmetric Synthetic Access to the Hetisine Alkaloids: Total Synthesis of (+)‐Nominine

Peese

Gin

2008

Chemistry A European J

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“…This choice would permit adoption of (+)-podocarpic acid (4) as starting material. [24][25][26]. The end of this fruitful and exciting experience coincided with the disclosure of the first two syntheses of (±)-aphidicolin (1) [7,8].…”

Section: Synthesis Of 17-noraphidicolan-16-one and 17-norstemodamentioning

confidence: 86%

“…Between 1976 and 1978 one of us (RMB) had been involved, as a member of the Wiesner group at the University of New Brunswick (Fredericton, NB, Canada), in the synthesis of some diterpene alkaloids whose C/D ring system, constituted by a bicyclo [ [24][25][26]. The end of this fruitful and exciting experience coincided with the disclosure of the first two syntheses of (±)-aphidicolin (1) [7,8].…”

Section: Synthesis Of 17-noraphidicolan-16-one and 17-norstemodamentioning

confidence: 99%

(+)-Podocarpic Acid as Chiral Template in the Synthesis of Aphidicolane, Stemodane and Stemarane Diterpenoids †

et al. 2016

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Abstract:In this review the synthetic work in the field of aphidicolane, stemodane and stemarane diterpenoids, in which readily available (+)-podocarpic acid (4) was used as chiral template for the construction of their polycyclic structures, is described as it developed along the years. In the frame of this work (+)-podocarpic acid (4) was a very useful tool in a model study leading to the syntheses of tetracyclic ketones 7 and 8, models of key intermediates 5a and 6 in the syntheses of (+)-aphidicolin (1) and (+)-stemodin (2a), respectively. (+)-Podocarpic acid (4) was also converted into (+)-2-deoxystemodinone (2d), allowing confirmation of the stemodane diterpenoids absolute configuration, into (+)-aphidicol-15-ene (36) and into Stemodia chilensis tetracyclic diterpenoid (+)-19-acetoxystemodan-12-ol (2f), allowing confirmation of its structure. (+)-Podocarpic acid (4) was then extensively used in the work which led to the synthesis of (+)-stemar-13-ene (57) and (+)-18-deoxystemarin (3b). Finally, (+)-4 was converted into (+)-2-deoxyoryzalexin S (66), which made it possible to demonstrate that the structure of (+)-66 could not be attributed to a Chilean Calceolaria isolated diterpenoid to which this structure had been assigned.

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“…Oxidation then gave diketone 108 which was converted to (±)-napelline ( 14 ) in 10 steps. In a later study, 53c the Wiesner group was able to convert a molecule with the atisane-based denudatine skeleton ( 109 ) to the kaurane-based napelline skeleton ( 110 ), by heating in acetic acid (Scheme 4b) via a process similar to the proposed biomimetic transformation shown in Fig. 4c.…”

Section: Diterpenoid Alkaloidsmentioning

confidence: 98%

“…The three diterpenoid-alkaloids that best highlight Wiesner’s landmark work on aconitine alkaloids are the C 20 alkaloid napelline ( 14 ), 53 and the C 19 alkaloids deoxydelphonine ( 15 ) 54 and talatisamine ( 13 ). 55 The total synthesis of napelline (Scheme 4a) commences from aldehyde 100 .…”

Section: Diterpenoid Alkaloidsmentioning

confidence: 99%

Terpenoid‐Alkaloids: Their Biosynthetic Twist of Fate and Total Synthesis

Cherney

Baran

2011

Israel Journal of Chemistry

101

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Terpenes and alkaloids are ever-growing classes of natural products that provide new molecular structures which inspire chemists and possess a broad range of biological activity. Terpenoid-alkaloids originate from the same prenyl units that construct terpene skeletons. However, during biosynthesis, a nitrogen atom (or atoms) is introduced in the form of β-aminoethanol, ethylamine, or methylamine. Nitrogen incorporation can occur either before, during, or after the cyclase phase. The outcome of this unique biosynthesis is the formation of natural products containing unprecedented structures. These complex structural motifs expose current limitations in organic chemistry, thus providing opportunities for invention. This review focuses on total syntheses of terpenoid-alkaloids and unique issues presented by this class of natural products. More specifically, it examines how these syntheses relate to the way terpenoid-alkaloids are made in Nature. Developments in chemistry that have facilitated these syntheses are emphasized, as well as chemical technology needed to conquer those that evade synthesis.

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A stereospecific synthesis of napelline

Cited by 41 publications

References 0 publications

Asymmetric Synthetic Access to the Hetisine Alkaloids: Total Synthesis of (+)‐Nominine

Asymmetric Synthetic Access to the Hetisine Alkaloids: Total Synthesis of (+)‐Nominine

(+)-Podocarpic Acid as Chiral Template in the Synthesis of Aphidicolane, Stemodane and Stemarane Diterpenoids †

Terpenoid‐Alkaloids: Their Biosynthetic Twist of Fate and Total Synthesis

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