1,3‐Dipolar Cycloaddition of Azomethine Ylides to Aldehydes: Synthesis of anti α‐Amino‐β‐Hydroxy Esters

Abstract

A 1,3-dipolar cycloaddition reaction of azomethine ylides to aldehydes is described. The azomethine ylides, generated by thermal electrocyclic ring opening of aziridines, adds to aldehydes in good yields with moderate to good selectivities to

1,3-Dipolar Cycloaddition Reactions of Azomethine Ylides with Carbonyl Dipolarophiles Yielding Oxazolidine Derivatives

“…The trans-ylide underwent a series of [3 + 2] cycloaddition reactions with mostly aromatic aldehydes 2 to form oxazolidines 40 and 41, with the cis-4,5-oxazolidines 40 being the major stereoisomers isolated. In most cases, reaction mixtures comprising both oxazolidines 40 and 41 were directly hydrolyzed to the corresponding α-amino-β-hydroxy esters 42 and 43, with the anti-diastereomer 42 formed as the major product (Scheme 8) [61]. More recently, Zhang and co-workers have disclosed an efficient, mild and general nickel(II)-catalyzed diastereoselective [3 + 2] cycloaddition reaction of N-tosylaziridine 2,2-dicarboxylates 44 with aromatic aldehydes 2 to afford highly substituted 1,3-oxazolidines 46 (Scheme 9, Table 5).…”

“…The trans-ylide underwent a series of [3 + 2] cycloaddition reactions with mostly aromatic aldehydes 2 to form oxazolidines 40 and 41, with the cis-4,5-oxazolidines 40 being the major stereoisomers isolated. In most cases, reaction mixtures comprising both oxazolidines 40 and 41 were directly hydrolyzed to the corresponding α-amino-β-hydroxy esters 42 and 43, with the anti-diastereomer 42 formed as the major product (Scheme 8) [61]. The thermal electrocyclic ring-opening of benzhydryl-protected aziridine 39 gives a cis-azomethine ylide in equilibrium with a trans-azomethine ylide.…”

Synthesis of functionalized dispiro-oxindoles through azomethine ylide dimerization and mechanistic studies to explain the diastereoselectivity

“…The rate of reaction is, somewhat, slower than the isatin reaction (Table 1) and trans-isomer was formed as major. N-Ethyl isatin (3) derived AMY underwent cycloaddition reaction in same condition and gave both isomers (12,13) in moderate yield. This reaction was slower than N-methyl isatin (2) case and completed in 8 h. The trans diastereomer ( 12) was found to be major and formed rst relative to cis diastereomer (13) (Table 1).…”

“…5 The routine [3 + 2]-cycloadditions of Azomethine ylide (AMY) are reported with a variety of dipolarophiles e.g. alkenes, [6][7][8][9][10] alkynes, 11 carbonyl compounds like aldehydes, 12 anhydrides, 13 imines 14 etc. and limited [3 + 3]-cycloadditions are also known to synthesize piperazine derivatives by self condensation of AMY.…”

One‐pot three‐component 1,3‐dipolar cycloaddition of azomethineylides to nitrofuran containing acetylenic ketones and molecular docking studies of the cycloadducts

“…[ 7–9 ] In addition to this, they may react with carbonyl compounds to yield oxazolidine derivatives. [ 10,11 ] Hence many reports are available in the literature for such cycloadditions, especially by using electron‐deficient alkenes and alkynes as dipolarophiles such as α,β‐unsaturated carbonyl compounds and nitro compounds. [ 12–15 ] The resulting adducts find enormous applications in pharmaceutics, catalysis, and agrochemicals.…”