Details
| Originalsprache | Englisch |
|---|---|
| Seiten (von - bis) | 2387-2400 |
| Seitenumfang | 14 |
| Fachzeitschrift | European Journal of Organic Chemistry |
| Ausgabenummer | 15 |
| Publikationsstatus | Veröffentlicht - 27 Apr. 2007 |
Abstract
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 upon as a latent dianion that can react either with two electrophiles or with bis-electrophiles, the latter transformation yielding ring-closure coproducts. It is advantageous if the electrophiles are epoxides or epoxides carrying a remote leaving group. The carbanion will ring-open the epoxide and allow a C→O silyl shift, thus generating the new carbanion. This then reacts with the second electrophile, either inter-or intramolecularly. The versatility of these two formyl anion equivalents is demonstrated by selected examples from natural product synthesis.
ASJC Scopus Sachgebiete
- Chemie (insg.)
- Physikalische und Theoretische Chemie
- Chemie (insg.)
- Organische Chemie
Zitieren
- Standard
- Harvard
- Apa
- Vancouver
- BibTex
- RIS
in: European Journal of Organic Chemistry, Nr. 15, 27.04.2007, S. 2387-2400.
Publikation: Beitrag in Fachzeitschrift › Survey Paper › Forschung › Peer-Review
}
TY - JOUR
T1 - Small and versatile
T2 - Formyl anion and dianion equivalents
AU - Kirschning, Andreas
AU - Kujat, Christof
AU - Luiken, Silke
AU - Schaumann, Ernst
PY - 2007/4/27
Y1 - 2007/4/27
N2 - 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 upon as a latent dianion that can react either with two electrophiles or with bis-electrophiles, the latter transformation yielding ring-closure coproducts. It is advantageous if the electrophiles are epoxides or epoxides carrying a remote leaving group. The carbanion will ring-open the epoxide and allow a C→O silyl shift, thus generating the new carbanion. This then reacts with the second electrophile, either inter-or intramolecularly. The versatility of these two formyl anion equivalents is demonstrated by selected examples from natural product synthesis.
AB - 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 upon as a latent dianion that can react either with two electrophiles or with bis-electrophiles, the latter transformation yielding ring-closure coproducts. It is advantageous if the electrophiles are epoxides or epoxides carrying a remote leaving group. The carbanion will ring-open the epoxide and allow a C→O silyl shift, thus generating the new carbanion. This then reacts with the second electrophile, either inter-or intramolecularly. The versatility of these two formyl anion equivalents is demonstrated by selected examples from natural product synthesis.
KW - Asymmetric synthesis
KW - Carbanions
KW - Formyl anions
KW - Homologations
KW - Umpolung
UR - http://www.scopus.com/inward/record.url?scp=34250680264&partnerID=8YFLogxK
U2 - 10.1002/ejoc.200601003
DO - 10.1002/ejoc.200601003
M3 - Survey paper
AN - SCOPUS:34250680264
SP - 2387
EP - 2400
JO - European Journal of Organic Chemistry
JF - European Journal of Organic Chemistry
SN - 1434-193X
IS - 15
ER -