144635-03-0Relevant articles and documents
An efficient route for the allylation of arylaldehydes to give enantiopure homoallylic alcohols
Thorat, Prashant B.,Goswami, Santosh V.,Bhusare, Sudhakar R.
, p. 1324 - 1330 (2013/11/19)
An efficient asymmetric synthesis of homoallylic alcohols is described by the allylation of carbonyl compounds using organocatalysts as chiral directors in the presence of tin metal. The effect of chiral environment is also studied on the allylation reactions. This method allows us to obtain two different enantiomers of homoallylic alcohol in the presence of the corresponding chiral compound. The protocol is applied to various aldehydes to obtain high yields and excellent enantioselectivities for the corresponding homoallylic alcohols.
Enantioselective reduction of heteroaromatic β,γ-unsaturated ketones as an alternative to allylboration of aldehydes. Application: Asymmetric synthesis of SIB-1508Y
Felpin, Fran?ois-Xavier,Bertrand, Marie-Jo,Lebreton, Jacques
, p. 7381 - 7389 (2007/10/03)
Enantioselective reduction of heteroaromatic β,γ-unsaturated ketones was found to be an efficient and convenient alternative to the allylboration of corresponding aldehydes. This new method was used for the formal asymmetric synthesis of SIB-1508Y 2.
Chemoenzymatic synthesis of optically active heterocyclic homoallylic and homopropargylic alcohols
Singh, Satwinder,Kumar, Subodh,Chimni, Swapandeep Singh
, p. 2679 - 2687 (2007/10/03)
A chemoenzymatic methodology has been developed using indium-mediated allylation of heterocyclic aldehydes under aqueous conditions followed by Pseudomonas cepacia lipase-catalyzed enantioselective acylation of racemic homoallylic and homopropargylic alcohols in organic media. It is observed that the lipase immobilized on ceramic particles (PS-C Amano II) catalyzes the resolution in a highly enantioselective manner in less time as compared to the native enzyme (PS Amano). The approach provides new functionalized chiral synthons useful in the synthesis of natural and pseudonatural products.
Efficient enantiomeric synthesis of pyrrolidine and piperidine alkaloids from tobacco
Felpin,Girard,Vo-Thanh,Robins,Villieras,Lebreton
, p. 6305 - 6312 (2007/10/03)
An enantiomeric synthesis of six piperidine and pyrrolidine alkaloids, (S)-nornicotine 1, (S)-nicotine 2, (S)-anatabine 3, (S)-N-methylanatabine 4, (S)-anabasine 5, and (S)-N-methylanabasine 6, known as natural products in tobacco, was established from a common chiral homoallylic (S)-3-(1-azidobut-3-enyl)-pyridine 15. An intramolecular hydroboration-cycloalkylation of the homoallylic azide intermediate 15 served as the key step in the pyrrolidine ring formation. A ring closing metathesis reaction (RCM) of a diethylenic amine intermediate (S)-allyl-(1-pyridin-3-yl-but-3-enyl)-carbamic acid benzyl ester 20 served as the key step in the piperidine ring formation. From the commercially available 3-pyridinecarboxaldehyde 13, a short and convenient enantiomeric synthesis of tobacco alkaloids is described: (S)-nornicotine I (5 steps, with an overall yield of 70%), (S)-hicotine 2 (6 steps, 65%), (S)-anatabine 3 (8 steps, 30%), (S)-N-methylanatabine 4 (8 steps, 25%), (S)-anabasine 5 (8 steps, 35%), and (S)-N-methylanabasine 6 (8 steps, 25%).
A short and efficient synthesis of unnatural (R)-nicotine
Girard,Robins,Villieras,Lebreton
, p. 9245 - 9249 (2007/10/03)
A short and efficient synthesis of unnatural (R)-nicotine is described, in which the key step is an intramolecular hydroboration-cycloalkylation of an azido-olefin intermediate. The synthesis is achieved in only four steps, with an overall yield of 51% (or in six steps with an overall yield of 65%). (C) 2000 Elsevier Science Ltd.
Total synthesis of (S)-anabasine and (S)-anatabine
Felpin,Vo-Thanh,Robins,Villieras,Lebreton
, p. 1646 - 1648 (2007/10/03)
A chiral synthesis of (S)-anabasine and (S)-anatabine from 3-pyridinecarboxaldehyde, via a ring closing metathesis reaction (RCM) as the key step, is reported in 8 steps for both products with overall yields of 35% and 30%, respectively.
Chiral Synthesis via Organoboranes. 36. Exceptionally Enantioselective Allylborations of Representative Heterocyclic Aldehydes at -100 deg C under Salt-Free Conditions
Racherla, Uday S.,Liao, Yi,Brown, Herbert C.
, p. 6614 - 6617 (2007/10/02)
Chiral terpenyl-based allylborane reagents (Ter2*BCH2CH=CH2, 1-3) undergo facile condensation with representative heterocyclic aldehydes (HetCHO) at -100 deg C (in the absence of Mg2+ salts) and afford the corresponding homoallylic alcohols (HetCH*(OH)CH2CH=CH2, 12-19) in enantiomeric purities approaching 100percent ee.A new workup procedure involving 8-hydroxyquinoline (8-HQ) has been utilized for the convenient isolation of the product alcohols.
