Abstract
The simplest nitroalkene, nitroethylene, undergoes Lewis acid-promoted [4 + 2] cycloaddition with chiral vinyl ethers to afford cyclic nitronates with high diastereoselectivity. The resulting cyclic nitronates react with electron deficient alkenes to effect a face selective [3 + 2] cycloaddition. The origin of stereocontrol in the [3 + 2] cycloaddition is due to the single ring substituent, a remote acetal center. The scope and limitations of the use of nitroethylene as a 4π component in Lewis acid-promoted cycloadditions are documented and discussed. Additionally, concise syntheses of the pyrrolizidine alkaloids (+)-macronecine and (+)-petasinecine are presented.
Original language | English (US) |
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Pages (from-to) | 3045-3050 |
Number of pages | 6 |
Journal | Journal of Organic Chemistry |
Volume | 63 |
Issue number | 9 |
DOIs | |
State | Published - May 1 1998 |
ASJC Scopus subject areas
- Organic Chemistry