Oligocyclopropane Structural Units from Cationic Intermediates
摘要:
[GRAPHICS]syn- and anti-bis-cyclopropanes have been efficiently prepared through two distinct routes via the trapping of cyclopropylcarbinyl cationic intermediates. A ring-closing olefin metathesis for the formation of the necessary allylsilane precursors highlights the initial route. The cyclopropanation step proceeds in good yield to provide exclusively trans-vinylcyclopropanes. Iteration of the sequence has provided an efficient route to bis-cyclopropanes. The stereospecificity of the second cyclization was shown to be dependent on distal functionality. An alternative approach produces these interesting structural units from skipped dienes in a single step.
Oligocyclopropane Structural Units from Cationic Intermediates
摘要:
[GRAPHICS]syn- and anti-bis-cyclopropanes have been efficiently prepared through two distinct routes via the trapping of cyclopropylcarbinyl cationic intermediates. A ring-closing olefin metathesis for the formation of the necessary allylsilane precursors highlights the initial route. The cyclopropanation step proceeds in good yield to provide exclusively trans-vinylcyclopropanes. Iteration of the sequence has provided an efficient route to bis-cyclopropanes. The stereospecificity of the second cyclization was shown to be dependent on distal functionality. An alternative approach produces these interesting structural units from skipped dienes in a single step.
Stereoselective approach to trisubstituted tetrahydrofurans
作者:Peter Mohr
DOI:10.1016/s0040-4039(00)73723-3
日期:1993.9
Functionalized allylsilanes 1 undergo with acetals 2 under mild Broensted acid catalysis a transacetalization-ring closure reaction to afford in fair to good yield and high diastereoselectivity all-cis-tetrahydrofurans 3. The stereochemical outcome is independent of the double bond geometry.
Oligocyclopropane Structural Units from Cationic Intermediates
作者:Richard E. Taylor、F. Conrad Engelhardt、Haiqing Yuan
DOI:10.1021/ol990221d
日期:1999.10.1
[GRAPHICS]syn- and anti-bis-cyclopropanes have been efficiently prepared through two distinct routes via the trapping of cyclopropylcarbinyl cationic intermediates. A ring-closing olefin metathesis for the formation of the necessary allylsilane precursors highlights the initial route. The cyclopropanation step proceeds in good yield to provide exclusively trans-vinylcyclopropanes. Iteration of the sequence has provided an efficient route to bis-cyclopropanes. The stereospecificity of the second cyclization was shown to be dependent on distal functionality. An alternative approach produces these interesting structural units from skipped dienes in a single step.