Asymmetric Synthesis of 4-Hydroxy-3-phenyltetrahydroisoquinoline Derivatives Using Enantiopure Sulfinimines (N-Sulfinyl Imines)
摘要:
Addition of lateral lithiated amides and phthalide anions to enantiopure sulfinimines (N-sulfinyl imines) represents a new approach for the asymmetric synthesis of 3-substituted isoquinolones and 3-substituted 4-hydroxy isoquinolones, respectively, important chiral building blocks for isoquinoline alkaloid synthesis. In one example 3-phenylisoquinolone (-)-15b was prepared in >95% ee by treatment of amide ion 10b with sulfinimine (S)-(+)-11 and subsequent deprotection of the N-sulfinyl auxiliary and cyclization. Oxaziridine-mediated hydroxylation of the anion of 16 afforded 4-hydroxy isoquinolone 19, which was transformed into 4-hydroxy-3-phenyltetrahydroisoquinoline (-)-22. In another approach 22 was prepared more directly by addition of phthalide ion 26 to (S)(+)-11, creating the two stereogenic centers simultaneously. The selectivity proved to be highly counterion dependent.
Asymmetric Synthesis of 4-Hydroxy-3-phenyltetrahydroisoquinoline Derivatives Using Enantiopure Sulfinimines (N-Sulfinyl Imines)
摘要:
Addition of lateral lithiated amides and phthalide anions to enantiopure sulfinimines (N-sulfinyl imines) represents a new approach for the asymmetric synthesis of 3-substituted isoquinolones and 3-substituted 4-hydroxy isoquinolones, respectively, important chiral building blocks for isoquinoline alkaloid synthesis. In one example 3-phenylisoquinolone (-)-15b was prepared in >95% ee by treatment of amide ion 10b with sulfinimine (S)-(+)-11 and subsequent deprotection of the N-sulfinyl auxiliary and cyclization. Oxaziridine-mediated hydroxylation of the anion of 16 afforded 4-hydroxy isoquinolone 19, which was transformed into 4-hydroxy-3-phenyltetrahydroisoquinoline (-)-22. In another approach 22 was prepared more directly by addition of phthalide ion 26 to (S)(+)-11, creating the two stereogenic centers simultaneously. The selectivity proved to be highly counterion dependent.
Asymmetric Synthesis of 4-Hydroxy-3-phenyltetrahydroisoquinoline Derivatives Using Enantiopure Sulfinimines (<i>N</i>-Sulfinyl Imines)
作者:Franklin A. Davis、Yemane W. Andemichael
DOI:10.1021/jo991119x
日期:1999.11.1
Addition of lateral lithiated amides and phthalide anions to enantiopure sulfinimines (N-sulfinyl imines) represents a new approach for the asymmetric synthesis of 3-substituted isoquinolones and 3-substituted 4-hydroxy isoquinolones, respectively, important chiral building blocks for isoquinoline alkaloid synthesis. In one example 3-phenylisoquinolone (-)-15b was prepared in >95% ee by treatment of amide ion 10b with sulfinimine (S)-(+)-11 and subsequent deprotection of the N-sulfinyl auxiliary and cyclization. Oxaziridine-mediated hydroxylation of the anion of 16 afforded 4-hydroxy isoquinolone 19, which was transformed into 4-hydroxy-3-phenyltetrahydroisoquinoline (-)-22. In another approach 22 was prepared more directly by addition of phthalide ion 26 to (S)(+)-11, creating the two stereogenic centers simultaneously. The selectivity proved to be highly counterion dependent.