Stereoselective construction of all-carbon quaternary stereocenters by allylboration of chiral aldehydes: synthesis of a fragment of (+)-vibsanin A

Sakama, Akihiro; Nishimura, Yoshiyasu; Motohashi, Yuko; Yoshida, Keisuke; Takao, Ken Ichi

doi:10.1016/j.tet.2016.07.030

Cited by 4 publications

(6 citation statements)

References 57 publications

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“…The residue was purified by column chromatography on silica gel (EtOAc/hexane, 1:10) to provide 6.2 mg (12% for 2 steps) of 18-A / 18-B (dr = 14:1) and 38.1 mg (71% for 2 steps) of 18-C / 18-D (dr = 1:10). The spectral data of synthetic 18-A – D were identical to those of the authentic samples …”

Section: Methodsmentioning

confidence: 61%

“…We previously reported the construction of an all-carbon quaternary stereocenter by allylboration of d -glyceraldehyde acetonide 13 using geranylboronic acid pinacol ester 15 (Table , entry 1) . The γ-adducts bearing a quaternary stereocenter were obtained as four diasteromers 18-A – D , which were separated into (3 R )-isomers 18-A / 18-B (4 R /4 S = 9:1) and (3 S )-isomers 18-C / 18-D (4 R /4 S = 1:5) in yields of 5 and 71% based on 15 .…”

Section: Resultsmentioning

confidence: 99%

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Stereoselective Synthesis of the Tricyclic Core of (−)-Callophycoic Acid A

et al. 2020

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Two stereocontrolled routes to the tricyclic core of (−)-callophycoic acid A are described. Our synthetic strategy relied on stereoselective allylboration using a new allylboronate reagent to construct the all-carbon quaternary stereocenter in the core, followed by efficient radical cyclization or palladium-catalyzed reductive cyclization to form its multisubstituted cyclohexane ring. The tetrahydrooxepin ring was constructed by intramolecular etheration. This study provides the first method for the stereoselective synthesis of the characteristic tricyclic skeleton of callophycoic acids.

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Section: Methodsmentioning

confidence: 61%

Section: Resultsmentioning

confidence: 99%

Stereoselective Synthesis of the Tricyclic Core of (−)-Callophycoic Acid A

et al. 2020

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“…The allylboration of D-glyceraldehyde acetonide D-45 (prepared from D-mannitol in two steps) with geranylboronate (48) provided 49 as a 4S/4R = 5:1 mixture (Scheme 9). 20 The stereo- Lower fragment 44 was prepared from Barbier product 47 (Scheme 10, a). Benzylation of 47 followed by hydroboration/oxidation provided diol 50.…”

Section: Scheme 8 Construction Of the Quaternary Stereocenter By Barbiertype Allylationmentioning

confidence: 99%

Total Synthesis of Natural Products Using Intramolecular Nozaki–Hiyama–Takai–Kishi Reactions

Takao¹,

Ogura

Yoshida³

et al. 2020

Synlett

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In this Account, we describe our studies on the total synthesis of several natural products using intramolecular Nozaki–Hiyama–Takai–Kishi (NHTK) reactions. In each synthesis, an NHTK reaction is used to efficiently construct a medium-sized ring. These examples demonstrate the utility of the intramolecular NHTK reaction in natural product synthesis.1 Introduction2 Total Synthesis of (+)-Pestalotiopsin A3 Total Synthesis of (+)-Cytosporolide A4 Total Synthesis of (+)-Vibsanin A5 Total Syntheses of (+)-Aquatolide and Related Humulanolides6 Conclusion

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“…Thus, a method for stereoselective construction of all carbon quaternary stereocenters by allylboration was developed. 9 We have demonstrated the utility of this allylboration by using the major product 8 D as a chiral building block in a synthesis of lower fragment 11 from our synthesis of ( ) vibsanin A (3). 9 The synthetic route is similar to that in Scheme 3, and is not shown on account of limited space.…”

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confidence: 95%

“…7 Based on this idea, we have developed two methods for stereoselective synthesis of homoallylic alcohols containing all carbon quaternary stereocenters using such carbonyl allylation reactions, and applied these methods to synthetic studies of natural products. In this account, we describe our development of the zinc mediated Barbier type allylation 8 and allylboration 9 of a sugar derived aldehyde, and the syntheses of ( ) vibsanin A (3) 10 and the tricyclic skeleton of ( ) callophycoic acid A (4). 11…”

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confidence: 99%

The Stereoselective Construction of All-Carbon Quaternary Stereocenters by Allylations and Its Application to Synthetic Studies of Natural Products

Sakama¹,

Ogura²,

Yoshida

et al. 2020

J. Synth. Org. Chem. Jpn.

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The synthesis of organic compounds containing all carbon quaternary stereocenters through the addition of allylmetals to aldehydes is still a challenge. In this account we describe two methods to achieve this transformation stereoselectively: one involves the zinc mediated Barbier type allylation and the other allylboration of a sugar derived aldehyde. These methods were applied to the total synthesis of () vibsanin A, and the synthesis of the tricyclic core of () callophycoic acid A.

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Stereoselective construction of all-carbon quaternary stereocenters by allylboration of chiral aldehydes: synthesis of a fragment of (+)-vibsanin A

Cited by 4 publications

References 57 publications

Stereoselective Synthesis of the Tricyclic Core of (−)-Callophycoic Acid A

Stereoselective Synthesis of the Tricyclic Core of (−)-Callophycoic Acid A

Total Synthesis of Natural Products Using Intramolecular Nozaki–Hiyama–Takai–Kishi Reactions

The Stereoselective Construction of All-Carbon Quaternary Stereocenters by Allylations and Its Application to Synthetic Studies of Natural Products

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