Total Synthesis of Dermostatin A

Zhang, Yingchao; Arpin, Carolynn C.; Cullen, Aaron J.; Mitton‐Fry, Mark J.; Sammakia, Tarek

doi:10.1021/jo2012658

Cited by 37 publications

(23 citation statements)

References 81 publications

(52 reference statements)

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“…Schreiber was a pioneer of the two-directional chain extension/ terminus differentiation strategy [132] and his group has employed the approach in magnificent syntheses of a range of unsymmetrical targets, including hikizimycin [133] and mycoticins A and B. [134] This strategy remains popular, with recent examples including those from the laboratories of Zhang, [135] Metz, [136] Molinski, [137] Blakemore, [138] Nelson, [139] and Vogel. [140] Stockman and coworkers have reported the application of the two-directional approach in both target and diversity oriented synthesis.…”

Section: Independent Reactionsmentioning

confidence: 99%

Multi-Bond Forming Processes in Efficient Synthesis

Green¹,

Sherburn²

2013

Aust. J. Chem.

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An increasing number of synthetic organic chemists are embracing the philosophy of efficiency. Herein we highlight multi-bond forming processes, which form two or more new covalent bonds in a single synthetic operation. Such processes, which have the ability to rapidly increase structural complexity, are preeminent in contemporary synthetic organic chemistry. In this short review we classify, analyse, and contrast contemporary multi-bond forming processes, frame these cutting edge contributions within a historical context, and speculate on likely future developments in the area.

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Section: Independent Reactionsmentioning

confidence: 99%

Multi-Bond Forming Processes in Efficient Synthesis

Green¹,

Sherburn²

2013

Aust. J. Chem.

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“…[20] The authors found that subjecting 64 to PPTS in toluene at 110 °C allowed a trans-ketalization to give 65 with perfect diastereoselectivity. Although they observed a 9:1 mixture of internal acetal to terminal acetal, they were able to isolate 65a in 82% yield.…”

Section: Diastereotopic Group Selection and Configurational Definimentioning

confidence: 99%

“…The key building block was prepared through hydrogen borrowing catalysis (Scheme 19). [22] Using the simple, cheap, achiral starting material 67 , the authors were able to use an ( S )-Ir-SEGPHOS complex to catalyze a double anti -crotylation with 3-butenyl-2-acetate to give 68 .…”

Section: Diastereotopic Group Selection and Configurational Definimentioning

confidence: 99%

“…The oxopolyene macrolide dermostatin A (66) was synthesized by the Sammakia group with use of an early local desymmetrization of 64 (Scheme 17). [20] The authors found that subjecting 64 to PPTS in toluene at 110°C allowed a transketalization to give 65 with perfect diastereoselectivity. Although they observed a 9:1 mixture of internal acetal/terminal acetal, they were able to isolate 65a in 82 % yield.…”

Section: (B) Sammakia's Synthesis Of Dermostatin a (2011)mentioning

confidence: 99%

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Local Desymmetrization through Diastereotopic Group Selection: An Enabling Strategy for Natural Product Synthesis

Horwitz

Johnson

2017

Eur J Org Chem

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The application of desymmetrization strategies in chemical synthesis has allowed fundamentally new synthetic sequences that efficiently create dense and polyfunctional stereochemical arrays. Enantiotopic group discrimination has become a well-established method of global desymmetrization, while the conceptually unique strategy of local desymmetrization by diastereotopic group discrimination has its own advantages. This microreview focuses on the application of local desymmetrization in natural product synthesis and places a particular emphasis on the efficiency engendered by diastereotopic group discrimination. Local desymmetrization is subdivided into three distinct manifolds; examples under each paradigm are presented and compared.

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“…In 2011, Sammakia and coworkers described the total synthesis of the macrolide dermostatin A (133) [57]. In their synthetic approach, the authors coupled the boron enolate of the methyl ketone 130 with the aldehyde 131, which formed the aldol adduct 132 with excellent selectivity toward the 1,5-anti isomer.…”

Section: ) [48]mentioning

confidence: 99%

Asymmetric Induction in Aldol Additions

Dias¹,

Polo²,

Lucca³

et al. 2013

Modern Methods in Stereoselective Aldol Reactions

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The selectivity of aldol reactions involving kinetic enolates is related to various factors such as the nature of the Lewis acid (Li, Mg, B, Al, Ti, Sn, etc.), the presence of stereogenic centers in both the substrates and reagents, the nature of their substituents and the reaction conditions. Another factor of major importance is the nature of the enolate double bond (Z or E) [1].In general, it is well known that in aldol reactions involving metal enolates, which proceed through a six-membered cyclic transition state, the Z-enolate leads to the formation of 1,2-syn aldol adducts and the E-enolate affords aldol adducts with the 1,2-anti configuration. A rationalization for the observed selectivities of these aldol reactions was proposed by Zimmerman and Traxler (Scheme 5.1) [2]. According to this model, the nature of the double bond geometry plays a primary role in determining the energies of the competing transition states. For Z-enolates, the transition state TS2 is more destabilized than transition state TS1 because of the 1,3-diaxial interactions between the R 1 and R 3 substituents as well as between these substituents and one of the metal ligands (L). Therefore, the Z-enolate preferentially leads to the formation of the 1,2-syn aldol adduct.For the E-enolate, 1,3-diaxial interactions between the R 1 and R 3 substituents and between both R 1 and R 3 and one of the metal ligands are present in transition state TS4. Therefore, the 1,2-anti aldol adduct is obtained from the lower energy transition state TS3.Modern aldol reactions use preformed enolates to obtain good yields by preventing side reactions. This methodology has proven to be very effective for various Lewis acids derived from lithium, titanium, tin, and boron. By using preformed enolates with chiral substrates and reagents, it is possible to obtain aldol adducts with an excellent degree of asymmetric induction.The IUPAC defines asymmetric induction as the traditional term describing the preferential formation in a chemical reaction of one enantiomer (or diastereomer) over the other as a result of a chiral feature present in the substrate, reagent, catalyst, or the environment [3].

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Total Synthesis of Dermostatin A

Cited by 37 publications

References 81 publications

Multi-Bond Forming Processes in Efficient Synthesis

Multi-Bond Forming Processes in Efficient Synthesis

Local Desymmetrization through Diastereotopic Group Selection: An Enabling Strategy for Natural Product Synthesis

Asymmetric Induction in Aldol Additions

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