Cycloadditions. 46. Thermally induced intramolecular oxime olefin cycloadditions leading to N-bridgehead systems. Stereochemistry and molecular mechanics calculations
摘要:
The intramolecular oxime olefin cycloaddition (IOOC) of proline and pipecolinic acid derivatives proceeds thermally with a high degree of stereoselectivity to provide a new route to functionalized pyrrolizidines, indolizidines, or quinolizidines. The ring closure proceeds with simultaneous stereoselective introduction of three or four stereocenters. Molecular mechanics calculations have been refined to accurately predict not only which stereoisomer is preferred but also the syn and anti coupling constants in these tricyclic molecules.
A concise synthesis of (±) and a total synthesis of (+)-epiquinamide
摘要:
A total synthesis of the quinolizidine alkaloid (+)-epiquinamide 1 has been achieved starting from (-)-pipecolinic acid 3. The key step is the highly diastereoselective addition of a TBDMS-protected propargyl alcohol to a chiral aldehyde derived from 3 to give erythro alkynol 19, which is then easily transformed into the desired bicyclic skeleton. (c) 2006 Elsevier Ltd. All rights reserved.
HASSNER, ALFRED;MAURYA, RAKESH;PADWA, ALBERT;BULLOCK, WILLIAM H., J. ORG. CHEM., 56,(1991) N, C. 2775-2781
作者:HASSNER, ALFRED、MAURYA, RAKESH、PADWA, ALBERT、BULLOCK, WILLIAM H.
DOI:——
日期:——
A concise synthesis of (±) and a total synthesis of (+)-epiquinamide
作者:Sok Teng (Amy) Tong、David Barker
DOI:10.1016/j.tetlet.2006.05.092
日期:2006.7
A total synthesis of the quinolizidine alkaloid (+)-epiquinamide 1 has been achieved starting from (-)-pipecolinic acid 3. The key step is the highly diastereoselective addition of a TBDMS-protected propargyl alcohol to a chiral aldehyde derived from 3 to give erythro alkynol 19, which is then easily transformed into the desired bicyclic skeleton. (c) 2006 Elsevier Ltd. All rights reserved.
Cycloadditions. 46. Thermally induced intramolecular oxime olefin cycloadditions leading to N-bridgehead systems. Stereochemistry and molecular mechanics calculations
作者:Alfred Hassner、Rakesh Maurya、Albert Padwa、William H. Bullock
DOI:10.1021/jo00008a038
日期:1991.4
The intramolecular oxime olefin cycloaddition (IOOC) of proline and pipecolinic acid derivatives proceeds thermally with a high degree of stereoselectivity to provide a new route to functionalized pyrrolizidines, indolizidines, or quinolizidines. The ring closure proceeds with simultaneous stereoselective introduction of three or four stereocenters. Molecular mechanics calculations have been refined to accurately predict not only which stereoisomer is preferred but also the syn and anti coupling constants in these tricyclic molecules.