First Diastereoselective Chiral Synthesis of (−)-Securinine
摘要:
A diastereoselective total synthesis of securinine in optically pure form was achieved by employing ring-closing metathesis of the corresponding dienyne compound as a key step.
Carboxy-directed asymmetric hydrogenation of α-alkyl-α-aryl terminal olefins: highly enantioselective and chemoselective access to a chiral benzylmethyl center
A carboxy-directedasymmetrichydrogenation of α-alkyl-α-aryl terminal olefins was developed by using a chiral spiro iridium catalyst, providing a highly efficient approach to the compounds with a chiral benzylmethyl center. The carboxy-directedhydrogenation prohibited the isomerization of the terminal olefins, and realized the chemoselective hydrogenation of various dienes. The concise enantioselective
of hydroxy enynes for the synthesis of bicyclo[4.3.0]non-1(9)-en-2-ones is disclosed, which can be rationalised through a cascade reaction of a dissociative Meyer–Schuster rearrangement to allenyl vanadates, followed by a thermal intramolecularDiels–Alder (IMDA) reaction and hydrolytic regeneration of the catalyst.
Synthesis of cis-2,5-disubstituted pyrrolidines via diastereoselective reduction of N-acyl iminium ions
作者:Alexander C Rudolph、Rainer Machauer、Stephen F Martin
DOI:10.1016/j.tetlet.2004.04.122
日期:2004.6
A new procedure for forming cis-2,5-disubstituted pyrrolidines having unsaturated side chains has been developed that features the diastereoselective reduction of N-acyl iminiumions, which were formed in situ by acid-catalyzed cyclizations of unsaturated γ-keto carbamates, with triphenylsilane. The sequence was applied to a very concise synthesis of 16, a subunit in the nonpeptide cholecystokinin
Cyclic 1,2-dinitrogen compounds through N,N′-di(methoxycarbonyl)hydrazinium intermediates
作者:Floris P.J.T. Rutjes、Henk Hiemstra、Hendrik H. Mooiweer、W.Nico Speckamp
DOI:10.1016/s0040-4039(00)88492-0
日期:1988.1
Acid catalyzed cyclization of methoxymethyl substituted acyclichydrazides 4 provides cyclichydrazides 5 in moderate to good yields through the intermediacy of N,N′-di(methoxycarbonyl)hydrazinium intermediates.
Silyl Enol Ether Prins Cyclization: Diastereoselective Formation of Substituted Tetrahydropyran-4-ones
作者:Gidget C. Tay、Chloe Y. Huang、Scott D. Rychnovsky
DOI:10.1021/jo501580p
日期:2014.9.19
developed. The key step of this methodology, a silyl enolether Prins cyclization, was promoted by a condensation reaction between a hydroxy silyl enolether and an aldehyde to afford substituted tetrahydropyran-4-ones. The cyclization was tolerant of many functional groups, and the modular synthesis of the hydroxy silyl enolether allowed for the formation of more than 30 new tetrahydropyran-4-ones with