Search results
Search for "hydrogenolysis" in Full Text gives 159 result(s) in Beilstein Journal of Organic Chemistry.
Recent progress on the total synthesis of acetogenins from Annonaceae
Beilstein J. Org. Chem. 2008, 4, No. 48, doi:10.3762/bjoc.4.48
- alcohol 215. Tosylation and hydrogenolysis with LiEt3BH removed the C-30 OTs group affording the SEM ether 216. The remaining steps for the completion of total synthesis of asiminecin were carried out along the lines described for asiminocin. Total synthesis of (+)-(30S)-bullanin (+)-Bullanin was isolated
- employed the (R)-α-OSEM allylic stannane 261 reaction with the dialdehyde 262 obtained from (S,S)-diethyl tartrate to afford the bis-adduct 263 (Scheme 36). Treatment of 263 with TBAF led to the core bis-THF intermediate, diol 264. Mono tosylation and subsequent hydrogenolysis with LiBEt3H gave alcohol 265
The first preparative solution phase synthesis of melanotan II
Beilstein J. Org. Chem. 2008, 4, No. 39, doi:10.3762/bjoc.4.39
- coupled with another dipeptide 5 using a combination of N,N′-dicyclohexylcarbodiimide (DCC) and N-hydroxynorbornene-2,3-dicarboximide (HONb) to yield a tetrapeptide product 7. The latter was subjected to catalytic hydrogenolysis leading to tetrapeptide salt 8 with an uncapped N-terminus. Hydrochloride of
Sordarin, an antifungal agent with a unique mode of action
Beilstein J. Org. Chem. 2008, 4, No. 31, doi:10.3762/bjoc.4.31
- -unsaturated ester, which was subjected to Pearlman hydrogenolysis of the benzyl group and selective catalytic reduction of the non-conjugated olefin with iridium black. The latter step proceeded in a predominately syn manner to afford intermediate 12, which was oxidized to cyclopentadiene 13 through TBS
- ether 80 was prepared via ethylene glycol protection, saponification, alkylation by prenyl bromide, hydrogenation and acetonide cleavage. Two other analogs were assembled from 70 by LiOH hydrolysis of the benzoate ester and Pd/C hydrogenolysis of the benzyl one. While biological tests indicated that
Analogues of amphibian alkaloids: total synthesis of (5R,8S,8aS)-(−)-8-methyl- 5-pentyloctahydroindolizine (8-epi-indolizidine 209B) and [(1S,4R,9aS)-(−)-4-pentyloctahydro- 2H-quinolizin- 1-yl]methanol
Beilstein J. Org. Chem. 2008, 4, No. 5, doi:10.1186/1860-5397-4-5
- slowly to a stirred suspension of the hydride in diethyl ether (Scheme 4). If the order of addition were reversed, the best yield obtained was 48%. The amino alcohol was protected as its tert-butyl(dimethyl)silyl ether (−)-31 (99%) before hydrogenolysis of the benzyl groups over Pearlman's catalyst in
A divergent asymmetric approach to aza-spiropyran derivative and (1S,8aR)-1-hydroxyindolizidine
Beilstein J. Org. Chem. 2007, 3, No. 41, doi:10.1186/1860-5397-3-41
- -cleavage/cyclication, and O-debenzylation. In searching for a more concise method, amino alcohol 8 was mesylated (MsCl, NEt3, 0 °C) and the resultant labile mesylate 12 was subjected to catalytic hydrogenolysis (H2, l atm, 10% Pd/C, r.t.), which gave (1S,8aR)-1-hydroxyindolizidine (ent-3) in 60% overall
An asymmetric synthesis of all stereoisomers of piclavines A1-4 using an iterative asymmetric dihydroxylation
Beilstein J. Org. Chem. 2007, 3, No. 37, doi:10.1186/1860-5397-3-37
- ])-16 in 94%. It is impossible to utilize hydrogenolysis due to reactivity of the acetylene unit. Indeed, the N-protecting group exchange of benzyloxycarbonyl (Cbz) for 2,2,2-trichloroethoxycarbonyl (Troc) in 17 was examined. The use of basic reagents such as Ba(OH)2[11] and KOH[12] failed to afford
A convenient allylsilane- N-acyliminium route toward indolizidine and quinolizidine alkaloids
Beilstein J. Org. Chem. 2007, 3, No. 32, doi:10.1186/1860-5397-3-32
- with one equivalent of stannic chloride resulted in the formation of 10 via the acyliminium ion intermediate 11. Subsequent oxidation of alcohol 10 with pyridinium dichromate, then catalytic hydrogenation (H2 over Pd/C) of ketone 12 induced hydrogenolysis of the CBz group, reduction of the double bond
Diastereoselective synthesis of some novel benzopyranopyridine derivatives
Beilstein J. Org. Chem. 2006, 2, No. 25, doi:10.1186/1860-5397-2-25
- hydrogenolysis of 5a (Scheme 1). The reaction mechanism is suggested to follow a ketal deprotection sequence to arrive at the 4-piperidone derivative, which is protonated and reacts with the aromatic ring to afford the six member heterocycle. Deprotonation restores the aromatic ring and subsequent elimination of
Hydrogenation of aromatic ketones, aldehydes, and epoxides with hydrogen and Pd(0)EnCat™ 30NP
Beilstein J. Org. Chem. 2006, 2, No. 15, doi:10.1186/1860-5397-2-15
- that different side reactions can take place like aromatic ring hydrogenation, as well as hydrogenolysis of the produced alcohol to the hydrocarbon derivative. [5][6] Some of these problems have been circumvented by adding ethylenediamine, [7] although this can make isolation of the product and
- University described the selective reduction of electron deficient and neutral aryl ketones to benzylic alcohols using Pd(0)EnCat™ 30NP as catalyst and a mixture of HCOOH/Et3N as the source of hydrogen [16]. Under these conditions they also achieved the chemoselective hydrogenolysis of aryl epoxides [17
- were obtained. The results are summarized in Table 2. trans-Stilbene oxide was chosen as a model for the hydrogenolysis of aromatic epoxides. The effect of different heterogeneous palladium catalysts and their propensity to over-reduce the benzylic alcohol generated after hydrogenolysis of the epoxide
Other Beilstein-Institut Open Science Activities
