161389-62-4Relevant academic research and scientific papers
Acetylenic vinyllithiums: Consecutive cycloisomerization-[4 + 2] cycloaddition reactions
Bailey, William F.,Wachter-Jurcsak, Nanette M.,Pineau, Mark R.,Ovaska, Timo V.,Warren, Rachel R.,Lewis, Carl E.
, p. 8216 - 8228 (2007/10/03)
Acetylenic vinyllithiums (2), which were generated from the corresponding acetylenic vinyl bromides (3) by low-temperature lithium-bromine exchange, cyclize on warming to give, following quench with water, isomerically pure conjugated bis-exocyclic 1,3-dienes (1) in good to excellent yield. Both five-membered and six-membered outer-ring dienes may be prepared: 5-exo closure of an acetylenic vinyllithium, which proceeds with total stereocontrol via syn-addition to give the E-isomer of a five-membered outer-ring diene, tolerates aryl-, silyl-, or alkyl-substituents at the distal acetylenic carbon; the corresponding 6-exo process is less facile and seems to be confined to substrates bearing an anion-stabilizing substituent, such as phenyl or trimethylsilyl, at the terminal acetylenic carbon. The highly reactive bis-exocyclic 1,3-dienes serve as precursors to polycyclic materials through subsequent Diels-Alder reaction with a wide variety of dienophiles. The consecutive exchange-cyclization-cycloaddition methodology, which can be conducted in one pot without isolation of intermediates, provides an efficient, operationally simple, and diastereoselective route to diverse polycyclic ring systems.
Cycloisomerization of Acetylenic Vinyllithiums: Sequential Anionic Cyclization - Cycloaddition as a Route to Polycyclic Ring Systems
Ovaska, Timo V.,Warren, Rachel R.,Lewis, Carl E.,Wachter-Jurcsak, Nanette,Bailey, William F.
, p. 5868 - 5870 (2007/10/02)
Acetylenic vinyllithiums, generated by low-temperature metal-halogen exchange, were found to undergo facile 5-exo-dig cyclization to afford isomerically pure conjugated 1,3-bis-exocyclic dienes which serve as reactive precursors to complex polycyclic mate
