On the Reactivity of 1-Amino-3-siloxy-1,3-dienes:  Kinetics Investigation and Theoretical Interpretation

Kozmin, Sergey A.; Green, Michael T.; Rawal, Viresh H.

doi:10.1021/jo990923g

Cited by 45 publications

(44 citation statements)

References 35 publications

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“…[23] The computed B3LYP/6-31G structures of thiazoles 1i-m in their reactive s-cis conformations are shown in Figure 2. [23] The computed B3LYP/6-31G structures of thiazoles 1i-m in their reactive s-cis conformations are shown in Figure 2.…”

Section: Homo Energies Of Thiazolesmentioning

confidence: 99%

4‐Alkenyl‐2‐aminothiazoles: Smart Dienes for Polar [4 + 2] Cycloadditions

et al. 2012

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An exhaustive investigation into the [4 + 2] cycloadditions of 4‐alkenyl‐2‐aminothiazoles with a wide range of dienophiles has been carried out. 4‐Alkenyl‐2‐aminothiazoles act as good in‐out dienes, reacting with dienophiles bearing electron‐withdrawing groups. The heteroannulations, typically conducted under mild conditions, were endo‐selective when cyclic dienophiles were used, and regioselective when the reactions are conducted with unsymmetrical dienophiles. The endo‐selective processes presumably take place by concerted but highly asynchronous mechanisms. In contrast, the low levels of endo selectivity and the lack of stereospecificity in the reactions with certain acyclic dienophiles indicate a stepwise mechanism with a zwitterion as the most plausible intermediate. The course of the reaction changes when the highly reactive PTAD and TCNE are used as dienophiles, since in these cases, only addition products were obtained. Calculations of the HOMO and LUMO energy values of representative 4‐alkenyl‐2‐aminothiazoles, and the results of π‐facial diastereoselective processes by using chiral substrates are also disclosed.

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Section: Homo Energies Of Thiazolesmentioning

confidence: 99%

4‐Alkenyl‐2‐aminothiazoles: Smart Dienes for Polar [4 + 2] Cycloadditions

et al. 2012

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“…9–11 Reaction of 4b with the lithium enolate of acetone, as well as with acetone silyl enol ether, furnished desired δ-chloro-β-hydroxyketones 21 and 22 with good yields and good, complimentary anti-anti - and syn-anti -stereoselectivities, respectively. And reaction of 4b with Rawal-Kozmin’s diene 12 smoothly afforded the hetero-Diels-Alder product 23 as a single stereoisomer.…”

mentioning

confidence: 99%

Rapid, One-Pot Synthesis of β-Siloxy-α-haloaldehydes

2011

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The Mukaiyama cross aldol reaction of α-fluoro-, α-chloro-, and α-bromoacetaldehyde-derived (Z)-tris(trimethylsilyl)- silyl enol ethers furnishing anti-β-siloxy-α-haloaldehydes is described. A highly diastereoselective, one-pot, sequential double aldol process, affording novel β,δ-bissiloxy-α,γ-bishaloaldehydes is developed. Reactions are catalyzed by C6F5CHTf2 and C6F5CTf2AlMe2 (0.5–1.5 mol%) and provide access to halogenated polyketide fragments.

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“…This high level of reactivity towards a rather unreactive and/or hindered dienophile is presumably due to the dimethylamino group being more electron donating [significantly raising its HOMO level] relative to Danishefsky’s diene. 54–56 In this fashion, high yields of the desired aminocyclohexene 25 were obtained. This key reaction sets the stereochemistry and provides us with extensive A-ring oxygenation.…”

Section: Resultsmentioning

confidence: 97%

“…59 This work represents the first approach in which the 12-membered D-ring of phomactin A was constructed simultaneously with the 1-oxadecalin at an early stage; one that is also amenable for an enantioselective total synthesis 49 through the use of Rawal’s asymmetric Diels-Alder cycloaddition. 54–56 …”

Section: Discussionmentioning

confidence: 99%

Constructing the architecturally distinctive ABD-tricycle of phomactin A through an intramolecular oxa-[3+3] annulation strategy

Buchanan

Cole

et al. 2011

Tetrahedron

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Our efforts in constructing the ABD-ring of phomactin A through an intramolecular oxa-[3 + 3] annulation strategy is described. This struggle entailed finding a practical and efficient preparation of annulation precursor, and a realization of the unexpected competing regioisomeric pathway. The success entailed accessing the A-ring through Diels-Alder cycloaddition of Rawal’s diene. Furthermore, the discovery that the regioisomers from the annulation existed as atropisomers with respect to the D-ring olefin and that they could be equilibrated to the desired ABD-tricycle, allowing large quantities of tricycle to be accessed.

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On the Reactivity of 1-Amino-3-siloxy-1,3-dienes: Kinetics Investigation and Theoretical Interpretation

Cited by 45 publications

References 35 publications

4‐Alkenyl‐2‐aminothiazoles: Smart Dienes for Polar [4 + 2] Cycloadditions

4‐Alkenyl‐2‐aminothiazoles: Smart Dienes for Polar [4 + 2] Cycloadditions

Rapid, One-Pot Synthesis of β-Siloxy-α-haloaldehydes

Constructing the architecturally distinctive ABD-tricycle of phomactin A through an intramolecular oxa-[3+3] annulation strategy

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