Tetrahydrofuran-Containing Macrolides: A Fascinating Gift from the Deep Sea

Lorente, Adriana; Lamariano‐Merketegi, Janire; Alberício, Fernando; Álvarez, Mercedes

doi:10.1021/cr3004778

Cited by 301 publications

(143 citation statements)

References 242 publications

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“…Hydrogen bonding involving both ester and ketone carbonyl groups ensures a well ordered transition state and helps to explain the high levels of diasterocontrol observed. When chiral rhodium catalysts (Rh 2 (S-DOSP) 4 , [25] Rh 2 (S-MEPY) 4 , [26] Rh 2 (S-TFPTTL) 4 , [27] and Rh 2 (S-PTAD) 4 [28] ) were used in reaction of diazo compound 1 with hydroxyketone 25, the tetrahydrofuran 36 was obtained in good yields but with no chiral induction (ee < 7%), whereas the use of copper(I) triflate in conjunction with chiral bisoxazoline ligand, 2,2-bis((4S)-(-)-4-isopropyloxazoline)-propane gave the product 36 (72%) in a low enantiomeric excess of 31% (Supporting Information). This suggests that the rhodium catalyzed process favors a metal free intermediate while the copper catalyst remains, at least to some extent, bound to the intermediate in accord with related work on metallocarbene asymmetric O-H insertion processes that are highly metal dependent, with copper being superior to rhodium.…”

Section: Scheme 4 Synthesis Of Poly-substituted Tetrahydrofurans By mentioning

confidence: 99%

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Stereoselective Synthesis of Highly Substituted Tetrahydrofurans through Diverted Carbene OH Insertion Reaction

et al. 2015

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Abstract:Copper or rhodium catalyzed reaction of diazocarbonyl compounds with β-hydroxyketones gives highly substituted tetrahydrofurans with excellent diastereoselectivity, under mild conditions, in a single step process that starts as a carbene O-H insertion reaction but is diverted by an intramolecular aldol reaction.The tetrahydrofuran ring is a commonly found motif in naturally occurring bioactive compounds, and occurs in structural classes such as lignans, [1] acetogenins, [2] ionophores, [3] and macrolides. [4] Examples include (+)-fragransin A2 [5] and amphidinolide F [6] (Figure 1). As a consequence, a number of strategies have been employed for the stereoselective synthesis of tetrahydrofurans. [7][8][9] However, despite advances in synthetic methodology, highly substituted tetrahydrofurans remain difficult to access, and new approaches are needed. We now describe a new route to highly substituted tetrahydrofurans that proceeds with excellent diastereoselectivity, under mild conditions in a single step (Scheme 1) by a novel process initiated by metallocarbene O-H insertion but diverted by intramolecular aldol reaction.

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Section: Scheme 4 Synthesis Of Poly-substituted Tetrahydrofurans By mentioning

confidence: 99%

“…[4] Examples include (+)-fragransin A2 [5] and amphidinolide F [6] (Figure 1). As a consequence, a number of strategies have been employed for the stereoselective synthesis of tetrahydrofurans.…”

Section: Introductionmentioning

confidence: 99%

Stereoselective Synthesis of Highly Substituted Tetrahydrofurans through Diverted Carbene OH Insertion Reaction

et al. 2015

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“…Several methodologies have been developed for the construction of THP rings towards the synthesis of natural products [2]. More recently, THF rings have been increasingly observed in the structures of new bioactive compounds, specifically macrolides, potentially due to their smaller molecular weight and less complex structures as compared to their THP counterparts [3].…”

Section: Introductionmentioning

confidence: 99%

Brønsted Acid-Catalyzed Direct Substitution of 2-Ethoxytetrahydrofuran with Trifluoroborate Salts

Fisher

Bolshan

2016

Catalysts

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Metal-free transformations of organotrifluoroborates are advantageous since they avoid the use of frequently expensive and sensitive transition metals. Lewis acid-catalyzed reactions involving potassium trifluoroborate salts have emerged as an alternative to metal-catalyzed protocols. However, the drawbacks to these methods are that they rely on the generation of unstable boron dihalide species, thereby resulting in low functional group tolerance. Recently, we discovered that in the presence of a Brønsted acid, trifluoroborate salts react rapidly with in situ generated oxocarbenium ions. Here, we report Brønsted acid-catalyzed direct substitution of 2-ethoxytetrahydrofuran using potassium trifluoroborate salts. The reaction occurs when tetrafluoroboric acid is used as a catalyst to afford functionalized furans in moderate to excellent yields. A variety of alkenyl-and alkynyltrifluoroborate salts readily participate in this transformation.

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“…1 Their prevalence has led to numerous methods for the efficient and selective synthesis of THFs with varying levels of substitution about the ring. Of the possible substitution patterns, 2,5-disubstituted THFs have received the most synthetic attention.…”

Section: Introductionmentioning

confidence: 99%

Oxidative cyclization of tertiary pentenol derivatives forming 2,5,5-trisubstituted THF rings and the total synthesis of cyclocapitelline

Phillips

Palmer

Stevens

et al. 2015

Tetrahedron Letters

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Tetrahydrofuran-Containing Macrolides: A Fascinating Gift from the Deep Sea

Cited by 301 publications

References 242 publications

Stereoselective Synthesis of Highly Substituted Tetrahydrofurans through Diverted Carbene OH Insertion Reaction

Stereoselective Synthesis of Highly Substituted Tetrahydrofurans through Diverted Carbene OH Insertion Reaction

Brønsted Acid-Catalyzed Direct Substitution of 2-Ethoxytetrahydrofuran with Trifluoroborate Salts

Oxidative cyclization of tertiary pentenol derivatives forming 2,5,5-trisubstituted THF rings and the total synthesis of cyclocapitelline

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