Diastereoselective Alkylation of Tricyclic Lactim Ethers

Abstract

Keywords: Asymmetric synthesis / Alkylations / Nitrogen heterocycles / TetrahydroisoquinolinesAlkylations of tricyclic 1-methoxy-3,6,11,11a-tetrahydro-4H-pyrazino[1,2-b]isoquinolin-4-one (5) were studied under various conditions. The highest conversions were obtained when LDA or LHMDS were used for the deprotonation step. The diastereoselectivity turned out to be highly dependent on the electrophile. While methyl iodide, isobutyl bromide, 4-methylpent-3-enyl bromide, and isopropyl bromide yielded mixtures of trans and cis diastereomers 10 and 11, respect-

Diversity-oriented synthesis of medicinally important 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (Tic) derivatives and higher analogs

“…These compounds are useful for the synthesis of piperazine isoquinoline derivatives and also act as useful building blocks for natural product syntheses. 48,49 Lemaire and co-workers 50 have reported the effect of solvent on the stereochemical outcome of the Pictet-Spengler reaction. In this regard, L-dopa 75a was treated with benzaldehyde in the presence of K 2 CO 3 using various polar solvents to give cis-and trans-Tic derivatives 100 and 101 respectively (Scheme 17).…”

Diversity-oriented synthesis of medicinally important 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (Tic) derivatives and higher analogs

“…These compounds are useful for the synthesis of piperazine isoquinoline derivatives and also act as useful building blocks for natural product syntheses. 48,49 Lemaire and co-workers 50 have reported the effect of solvent on the stereochemical outcome of the Pictet-Spengler reaction. In this regard, L-dopa 75a was treated with benzaldehyde in the presence of K 2 CO 3 using various polar solvents to give cis-and trans-Tic derivatives 100 and 101 respectively (Scheme 17).…”

Diversity-oriented synthesis of medicinally important 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (Tic) derivatives and higher analogs

“…These compounds are useful for the synthesis of piperazine isoquinoline derivatives and also act as useful building blocks for natural product syntheses. 48,49 Lemaire and co-workers 50 have reported the effect of solvent on the stereochemical outcome of the Pictet-Spengler reaction. In this regard, L-dopa 75a was treated with benzaldehyde in the presence of K 2 CO 3 using various polar solvents to give cis-and trans-Tic derivatives 100 and 101 respectively (Scheme 17).…”

Diversity-oriented synthesis of medicinally important 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (Tic) derivatives and higher analogs

“…These compounds are useful for the synthesis of piperazine isoquinoline derivatives and also act as useful building blocks for natural product syntheses. 48,49 Lemaire and co-workers 50 have reported the effect of solvent on the stereochemical outcome of the Pictet-Spengler reaction. In this regard, L-dopa 75a was treated with benzaldehyde in the presence of K 2 CO 3 using various polar solvents to give cis-and trans-Tic derivatives 100 and 101 respectively (Scheme 17).…”