1338698-49-9Relevant academic research and scientific papers
Synthesis of triazolo isoquinolines and isochromenes from 2-alkynylbenzaldehyde via domino reactions under transition-metal-free conditions
Arigela, Rajesh K.,Samala, Srinivas,Mahar, Rohit,Shukla, Sanjeev K.,Kundu, Bijoy
, p. 10476 - 10484 (2013/11/06)
We describe two simple straightforward syntheses of triazolo isoquinolines (3) and isochromenes (7) from 2-alkynylbenzaldehydes (1) as a common synthon. The synthetic strategy for 3 involves formation of the (E)-1-(2-nitrovinyl)-2- (alkynyl)benzene species 2 via condensation of synthon 1 with nitromethane followed by a [3 + 2] cycloaddition/extrusion of the nitro group/regioselective 6-endo cyclization domino sequence. In yet another strategy, the synthon 1 was condensed with nitromethane followed by electrophilic iodo cyclization of the resulting 2-nitro-1-(2-(alkynyl)phenyl)ethanol (6) to furnish iodo isochromene derivatives. The salient feature of the above two strategies involves formation of the corresponding heterocycles under metal-free conditions in good yields.
Copper(II)-catalyzed asymmetric henry reaction of o-alkynylbenzaldehydes followed by gold(I)-mediated cycloisomerization: An enantioselective route to chiral 1 H-isochromenes and 1,3-dihydroisobenzofurans
Lu, Dengfu,Zhou, Yirong,Li, Yajun,Yan, Shaobai,Gong, Yuefa
experimental part, p. 8869 - 8878 (2011/12/15)
By combining the copper(II)-catalyzed asymmetric Henry reaction of o-alkynylbenzaldehydes with subsequent gold(I)-catalyzed cycloisomerization, optically active 1H-isochromenes and 1,3-dihydroisobenzofurans were successfully synthesized in good overall yields with good to excellent enantioselectivities (up to 98%). Various substrates were investigated, and a correlation between the regioselectivity and electronic nature of the substrates was studied. The substrates with electro-donating groups at the alkynyl moiety preferred a 6-endo-dig manner to generated 1H-isochromenes 3 as main products (up to >30:1) while the ones with electron-withdrawing groups were inclined to undergo 5-exo-dig cyclization to form 1,3-dihydroisobenzofurans 4 (up to 1:5).
