Functionalized alanes for the conversion of epoxides to trans-fused .gamma.-lactones

Sodium diethyldialkylaluminate, a new chemoselective alkynylating agent

“…For example, SDAA reacted with 5-bromo-2-pentanone ( 9) to give 5-bromo-2-(phenylethynyl)pentan-2-ol (10) in an isolated yield of 79% at -20 °C. In contrast, lithium phenylacetylide gave 2-methyl-2-(phenylethynyl)tetrahydrofuran in 90% yield at 0 °C (85% even at -50 °C) instead of the expected product 10.…”

A New Method of Synthesis for Propargylic Amines and Ethers via Benzotriazole Derivatives Using Sodium Dialkynyldiethylaluminates

“…As reflected in Table , diethylphenylethynylaluminum ( 6 ) (entry 2) showed essentially quantitative conversion. However, it has been previously reported that alkynylaluminum reagents present poor chemoselectivity for carbonyl compounds and can react with other functional groups, such as halides and epoxides. − Consequently, despite the good yields listed in entry 2, we chose the more chemoselective sodium dialkynyldiethylaluminates 5 , 9 , and 11 as alkynylation reagents for reactions with benzotriazole derivatives 13 and 16a − j .…”

Epoxides in Complex Molecule Synthesis

“…Following the seminal work of Danishefsky [64], who introduced the use of Et 2 AlCl as an efficient catalyst for the reaction, Taylor obtained valuable spiro lactones through the addition reaction of the lithium enolate of tert-butyl acetate to spiro-epoxides, upon treatment of the corresponding g- hydroxy esters, the primary reaction product, with TsOH [65a]. Lithium enolates of esters have recently been used for the enantioselective synthesis of trisubstituted cyclopropanes [65b].…”