Showing papers by "Peter Wipf published in 1990"

Carboalumination of 1-alkynes and in situ transmetalation to higher order cyanocuprates. Stereospecific synthesis of tri- and disubstituted olefins by conjugate addition to enones

Abstract: A method for the selective cleavage of a benzodioxole (methylenedioxy group) to a methoxyphenol through the use of a p-methylthiophenoxide ion is described. When the procedure was applied to a lignan derivative such as (−)-austrobailignan-5, the reaction was found to proceed regioselectively, and the intermediate thiacetal could be converted to a catechol, or manipulated to yield either one of the two possible methoxyphenols. Of the two isomers, the one with the bis 3-methoxy-4-hydroxy substitution was found to be identical with (−)-dihydroguaiaretic acid, isolated for the first time from the plant Saururus cernuus

Use of a masked aldol unit in the synthesis of the right side of FK-506

Abstract: A strategy for the synthesis of the C 16 -C 27 right side portion of the immunosuppressant FK-506 is developed

Methodology for the enantioselective synthesis of aldols and other 1,3-dioxygenated systems

Abstract: The enantioselective synthesis of the spiroenones 3, 4 from(S)-glycidol-O-benzyl ether and lithiated furan derivatives is described. After conjugate addition of lithium dimethyl cuprate or lithium divinyl cuprate and conversion of the resulting saturated ketones to their respective iodides 7 and 8, fragmentation of these halides leads to the formation of acyclic aldol-containing carbon skeletons

Carboalumination of 1-Alkynes and in situ Transmetalation to Higher Order Cyanocuprates. Stereospecific Synthesis of Tri- and Disubstituted Olefins by Conjugate Addition to Enones.

Abstract: A method for the selective cleavage of a benzodioxole (methylenedioxy group) to a methoxyphenol through the use of a p-methylthiophenoxide ion is described. When the procedure was applied to a lignan derivative such as (−)-austrobailignan-5, the reaction was found to proceed regioselectively, and the intermediate thiacetal could be converted to a catechol, or manipulated to yield either one of the two possible methoxyphenols. Of the two isomers, the one with the bis 3-methoxy-4-hydroxy substitution was found to be identical with (−)-dihydroguaiaretic acid, isolated for the first time from the plant Saururus cernuus

Methodology for the Enantioselective Synthesis of Aldols and Other 1,3-Dioxygenated Systems.

Abstract: The enantioselective synthesis of the spiroenones 3, 4 from(S)-glycidol-O-benzyl ether and lithiated furan derivatives is described. After conjugate addition of lithium dimethyl cuprate or lithium divinyl cuprate and conversion of the resulting saturated ketones to their respective iodides 7 and 8, fragmentation of these halides leads to the formation of acyclic aldol-containing carbon skeletons