28338-69-4Relevant academic research and scientific papers
2-(Prenyloxymethyl)benzoyl (POMB) group: a new temporary protecting group removable by intramolecular cyclization
Vatèle, Jean-Michel
, p. 10921 - 10929 (2008/02/12)
2-(Prenyloxymethyl)benzoates can be prepared from alcohols and readily available 2-(prenyloxymethyl)benzoic acid by standard acylation techniques or by Mitsunobu reaction with inversion of configuration. The POMB group can be cleaved first by oxidative removal of the prenyl group with DDQ followed by lactonization with expulsion of the alcohol catalyzed by Yb(OTf)3. These reaction conditions are compatible with the presence of a large number of common protecting groups.
Chloromethanesulfonate as an efficient leaving group: Rearrangement of the carbon-carbon bond and conversion of alcohols into azides and nitriles
Shimizu, Takeshi,Ohzeki, Tomoya,Hiramoto, Katsuya,Hori, Nobuyuki,Nakata, Tadashi
, p. 1373 - 1385 (2007/10/03)
The chloromethanesulfonate (monochlate) served as an efficient leaving group for rearrangement of the carbon-carbon bond and conversion of alcohols into azides and nitriles. The treatment of the monochlate 16a with zinc acetate in dioxane at 90 °C effected migration of the 4α-methyl group to give alkene 17a. Upon similar treatment of the monochlates 22a, 25a, 28a, and 31a with zinc acetate, the carbon-carbon bonds antiperiplanar to the hydroxyl groups efficiently migrated to afford the alkenes 23a, 26a-c, 29a,b, and 32a, respectively. In the case of the diol 40, the monochlate was converted into the ketone 41 via a rearrangement-ring expansion. The reaction of the monochlates 44a, 47a, 49a, 52a, and 57a with sodium azide or lithium azide in N,N-dimethylformamide efficiently afforded the azides with inversion of the configuration. The introduction of a nitrile group to the sterically hindered alcohol 59 was performed in high yield by the reaction of the monochlate 60a with sodium cyanide.
A Convenient and High Yielding Procedure for the Preparation of Isoselenocyanates. Synthesis and Reactivity of O-Alkylselenocarbamates.
Barton, Derek H. R.,Parekh, Shyamal I.,Tajbakhsh, Mahmoud,Theodorakis, Emmanouil A.,Tse, Chi-Lam
, p. 639 - 654 (2007/10/02)
A high yielding one pot procedure for the preparation of isoselenocyanate from the corresponding formamide is reported.Various aromatic and aliphatic primary amines were employed in order to prepare the isoselenocyanates to establish the generality of the procedure.O-Alkylselenocarbamates of various primary, secondary and tertiary alcohols were synthesized and their stability and comparative reactivity were studied.Radical deoxygenation of the selenocarbamate of a secondary and a tertiary alcohol was accomplished under various conditions.
Stereocontrolled formation of cis and trans ring junctions in hydrindane, decalin, and steroid systems by palladium-catalyzed regioselective and stereospecific hydrogenolysis of allylic formates
Mandai, Tadakatsu,Matsumoto, Takaji,Kawada, Mikio,Tsuji, Jiro
, p. 5483 - 5493 (2007/10/02)
Both the cis and trans ring junctions can be generated selectively in hydrindane, decalin and steroid systems by the palladium-catalyzed regioselective and stereospecific decarboxylation-hydrogenolysis of allylic formates. The trans junctions were formed from 3β allylic formates of decalin and steroid and 5β allylic formates of hydrindane. The corresponding 3α and 5α formates generate the cis ring junction.
Stereocontrolled Formation of Cis and Trans Ring Junctions in Hydrindane and Decalin Systems by Palladium-Catalyzed Regioselective and Stereospecific Hydrogenolysis of Allylic Formates
Mandai, Tadakatsu,Matsumoto, Takaji,Kawada, Mikio,Tsuji, Jiro
, p. 1326 - 1327 (2007/10/02)
Both cis and trans ring junctions can be generated selectively in hydrindane, decalin, and steroid systems by the palladium-catalyzed regioselective and stereospecific hydrogenolysis of allylic formates.
Liquid-Crystalline Solvents as Mechanistic Probes. 18. The Micromorphology of Crystalline and Liquid-Crystalline Phases of 5-α-Cholestan-3β-yl trans-Cinnamate as Discerned from Photochemical Studies
Ramesh, Varadaraj,Weiss, Richard G.
, p. 13 - 22 (2007/10/02)
The photoreaction of 5α-cholestan-3β-yl trans cinnamate in its crystalline and liquid-crystalline phases and in isotropic solutions (n-hexane and n-hexadecane) have been investigated.In hydrocarbon solutions, geometric isomerization of the ester and its cleavage to cholestene and cinnamic acid are dominant processes; in the crystalline and liquid-crystalline phases, dimerization is the principal reaction mode.Only one photodimer, bis(5α-cholestan-3β-l) α-truxillate (head-t-tail), could be detected from the crystalline and liquid-crystalline phase experiments.The photochemistry of the liquid-crystalline phase of cholesteryl trans-cinnamate was reexamined and shown to proceed quite differently from that of the cholestanyl ester.
Stereochemistry and Regiochemistry of Electron Impact, Photolytically, and Thermally Induced Eliminations from 5α-Cholestanyl Acetates
Valente, C.,Eadon, G.
, p. 44 - 51 (2007/10/02)
Deuterium-labeled compounds were used to define the sterochemistry and regiochemistry of the electron impact induced eliminations of acetic acid from 5α-cholestanyl 3α-acetate, 4α-acetate, and 6α-acetate.Comparison of the electron impact induced eliminations to the pyrolysis and to the photolysis of the corresponding phenylacetates confirmed that the mass spectral elimination was a stepwise process proceeding through the stable chair conformation of the steroid's cyclohexyl ring.The equatorially oriented 4α- and 6α-acetates fragmented with predominant loss of asecondary trans-equatorial hydrogen, rather than the tertiary cis-axial hydrogen, despite the a priori greater migratory aptitude of tertiary hydrogens.The electron impact induced fragmentation of the 3α-acetate occured with predominant loss of a C-4 hydrogen; in contrast, the photolysis of the corresponding 3α-phenylacetate results in loss of a C-2 hydrogen.This results can be attributed to the reversibility of the photolytically induced hydrogen-abstraction step.
