Multicomponent Linchpin Couplings of Silyl Dithianes via Solvent-Controlled Brook Rearrangement

Smith, Iii and Amos B.; Boldi, Armen M.

doi:10.1021/ja970371o

Cited by 153 publications

(85 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…[51] HMPA or DMPU [52] have also been suggested as additives. [53] Considering the overall reaction towards 61, carbanion 57 reacts as a 1,1-dianion (see Scheme 1) with the second negative charge formed by silyl migration.…”

Section: Dianion Equivalents Based On Silylsubstituted Dithioacetalsmentioning

confidence: 99%

Small and Versatile – Formyl Anion and Dianion Equivalents

et al. 2007

View full text Add to dashboard Cite

This account provides a short overview of the synthetically important class of formyl anions and the less studied formyl dianion equivalents. A brief literature survey, which particularly focusses on asymmetric homologation strategies, is complemented by a detailed description of lithiated (dimethoxymethyl)diphenylphosphane oxide, which is an ideal formyl anion equivalent in reactions with aldehydes. Under acidic conditions the intermediate ketene O,O-acetals afford homologated carboxylic esters whereas asymmetric dihydroxylation of ketene acetals leads to collapse of the intermediate diols furnishing the corresponding α-hydroxy carboxylic esters with high stereocontrol. Additionally, it is demonstrated that the silyl-substituted carbanion may be looked

show abstract

Section: Dianion Equivalents Based On Silylsubstituted Dithioacetalsmentioning

confidence: 99%

Small and Versatile – Formyl Anion and Dianion Equivalents

et al. 2007

View full text Add to dashboard Cite

show abstract

“…of silyl dithianes with epoxides [57], Smith and Boldi prepared a protected 11-carbon fragment related to the 1,3-polyol half of the macrolide roflamycoin. Recently, using a powerful strategy similar to that of the synthesis of the calyculins described above (Scheme 12.…”

Section: Stepsmentioning

confidence: 99%

Multicomponent Reactions in the Total Synthesis of Natural Products

Touré

Hall

2005

Multicomponent Reactions

View full text Add to dashboard Cite

“…[5] In 1997, based on the early work by the groups of Matsuda, [6] Tietze, [7] and Oshima, [8] we introduced an example of the Type I ARC process involving mono-silyl dithianes, [9] which, in conjunction with a solvent-controlled Brook rearrangement, [10] led to the development of an effective threecomponent union protocol employing a wide variety of different second electrophiles. The utility of this process was subsequently demonstrated by completion of several natural product total syntheses, including (+)-spongistatins 1 and 2, [11] and more recently (À)-indolizidine 223AB and alkaloid (À)-205B, the latter two utilizing aziridine as the second electrophile.…”

mentioning

confidence: 99%

“…Building on our earlier successful incorporation of the dithiane, [9] nitrile, [4d] and allyl [4d] functionalities as ASGs in bifunctional linchpins, in conjunction with the recent work of Takeda, [13] Moser, [14] and Xian [15] , we reasoned that ortho-TMS benzaldehyde (3, TMS = trimethylsilyl) held considerable promise as an effective linchpin for the Type II ARC process. Specifically, the early work of Moser and co-workers [14] demonstrated that strong electron-withdrawing groups, for example a chromium tricarbonyl moiety, are required to facilitate the Brook rearrangement in aryl systems.…”

mentioning

confidence: 99%

Ortho‐TMS Benzaldehyde: An Effective Linchpin for Type II Anion Relay Chemistry (ARC)

Smith¹,

Kim²,

Wuest³

2008

Angew Chem Int Ed

View full text Add to dashboard Cite

Ortho-TMS benzaldehyde, an effective bifunctional linchpin for Type II Anion Relay Chemistry (ARC), permits efficient multi-component union of a variety of nucleophiles and electrophiles, including the first example of a Pd-mediated ARC Type II process. To demonstrate the utility of the Type II ARC protocol, a "proof of concept" synthetic sequence was designed and implemented for construction of a focused library of "natural product-like" compounds. Nature, with beautiful elegance, constructs natural products often in iterative fashion with both superb efficiency and exquisite stereochemical control.[1] For more than 100 years chemists have atempted to mimic the elegance of Nature with laboratory syntheses. The shortcomings of many synthetic ventures however lie in the multi-step sequences, often leading to minimum structure augmentation, in conjunction with isolation and purification at each stage, leading to inefficient material advancement. Fortunately, multi-component reactions[2] hold considerable promise of alleviating this inefficiency by orchestrating the conversion of simple starting materials, in a single (one-pot) operation, to advanced intermediates of high structural complexity without the need for multiple isolations and purifications.[3] Towards this end, we recently turned to the development of multi-component reaction sequences exploiting Anion Relay Chemistry (ARC).[4] At the highest level, the ARC tactic can be divided into two processes involving anion migration either through bonds or though space, the latter requiring the availability of a carrier to transport the negative charge. A simple example of "through-bond" anion relay is the well-known conjugate addition, through the π-system, with subsequent capture of the intermediate enolate. For "through-space" anion relay two possibilities exist involving σ-bonds (Type I and II), the difference residing in the resulting locus of the transposed anion. Type I ARC is defined as a multi-component coupling protocol (Scheme 1), wherein a linchpin nucleophile reacts with an electrophile to generate an oxyanion that subsequently transfers (i.e., relays) the negative charge "back" to the initiating site, followed by reaction with a suitable electrophile. The Type II process, entails reaction of a nucleophile with a bifunctional electrophilic linchpin to generate an anionic species that relays the negative charge to a new (i.e., different) locus, which then reacts with a second electrophile. An important feature of the Type II ARC process is the potential for iteration with a sequential series of bifunctional linchpins, a process not disimilar to living polymerization. [5] In 1997, based on the early work of Matsuda,[6] Tietze,[7] and Oshima,[8] we introduced an example of the Type I ARC process involving mono-silyl dithianes,[9] which through aegis of a solvent-controlled Brook rearrangement[10] led to the development of an effective three-component union protocol employing a wide variety of different second electrophiles. The utility of this process w...

show abstract

Multicomponent Linchpin Couplings of Silyl Dithianes via Solvent-Controlled Brook Rearrangement

Cited by 153 publications

References 34 publications

Small and Versatile – Formyl Anion and Dianion Equivalents

Small and Versatile – Formyl Anion and Dianion Equivalents

Multicomponent Reactions in the Total Synthesis of Natural Products

Ortho‐TMS Benzaldehyde: An Effective Linchpin for Type II Anion Relay Chemistry (ARC)

Contact Info

Product

Resources

About