Heck Arylation of Endocyclic Enecarbamates with Diazonium Salts. Improvements and a Concise Enantioselective Synthesis of (−)-Codonopsinine
作者:Elias A. Severino、Carlos Roque D. Correia
DOI:10.1021/ol005762d
日期:2000.10.1
Total enantioselective synthesis of the natural (-)-codonopsinine was accomplished in seven steps with an overall yield of approximately 16% starting from the five-membered endocyclic enecarbamate 4. The totalsynthesis features a highly efficient and stereoselective Heck arylation of endocyclic enecarbamate 4 with p-methoxybenzenediazonium tetrafluoroborate and a stereoselective epoxidation/epoxide
Synthesis of dihydroxylated prolines and iminocyclitols from five-membered endocyclic enecarbamates. Total synthesis of the potent glycosidase inhibitor (2R,3R,4R,5R)-2,5-dihydroxymethyl-3,4-dihydroxypyrrolidine (DMDP)
作者:Ariel Lázaro L Garcia、Carlos Roque D Correia
DOI:10.1016/s0040-4039(03)00017-0
日期:2003.2
cis- and trans-3,4-Dihydroxylated prolines and the iminocyclitol 1,4-dideoxy-1,4-imino ribitol were synthesized employing a strategy involving the Heck arylation of five-membered endocyclic enecarbarnates with aryldiazonium salts followed by oxidative cleavage of the electron-rich aromatic ring. The total synthesis of the potent alpha- and beta-glucosidase inhibitor (2R,3R,4R,5R)-2,5-hydroxymethyl-3,4-dihydroxypyrrolidine (DMDP) was also achieved by the same strategy in ten steps from a chiral five-membered enecarbamate in 12% overall yield. (C) 2003 Elsevier Science Ltd. All rights reserved.
Probing the Stereoselectivity of the Heck Arylation of Endocyclic Enecarbamates with Diazonium Salts. Concise Syntheses of (2<i>S</i>,5<i>R</i>)-Phenylproline Methyl Ester and Schramm's C-Azanucleoside
作者:Elias A. Severino、Edson R. Costenaro、Ariel L. L. Garcia、Carlos Roque D. Correia
DOI:10.1021/ol027268a
日期:2003.2.1
[GRAPHICS]The diastereoselectivity of the Heck arylation of several chiral, nonracemic, five-membered endocyclic enecarbamates with aryldiazonium tetrafluoroborates was evaluated. The cis selectivity observed for some enecarbamates bearing coordinating groups was explored in the concise synthesis of the (2S,5R)-(+)-phenylproline methyl ester, a scaffold for the nonpeptide cholecystokinin antagonist (+)-RP 66803, and in the synthesis of Schramm's potent antiprotozoan C-azanucleoside.