Abstract
Exocyclic allene natural products and pharmaceutical agents are rare but interesting compounds: Fucoxanthin, grasshopper ketone, and analogues of prostacyclins, cephalosporins, antithrombic agents and sterol biosynthesis inhibitors are representative. Syntheses of exocyclic allenes commonly rely on extended conjugate additions to e.g., alk-2-en-4-ynones, syn SN2′-like additions to alkynyl oxiranes, and substitution reactions such as electrophilic substitutions of propargylic silanes. We report that the reaction of 3-alkynyl-2-cycloalkenones with 2 equiv of various hydridoaluminates but not hydridoborates proceeds via diastereoselective 1,4-reduction of a vinylogously propargylic intermediate alcoholate to provide exocyclic allenes as major products. Isomeric 3-alkynylcycloalkanols also are observed.
Original language | English (US) |
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Pages (from-to) | 6052-6063 |
Number of pages | 12 |
Journal | Tetrahedron |
Volume | 72 |
Issue number | 40 |
DOIs | |
State | Published - 2016 |
All Science Journal Classification (ASJC) codes
- Biochemistry
- Drug Discovery
- Organic Chemistry