Cyclopentano[c]-s-triazoles were synthesized by intramolecular ringtransformation starting from y-keto-l,3,4-oxadiazoles 5 and 9. The required functionality for this intramolecular reaction was established by (i) the reaction of lithiated 2-methyl-l,3,4-oxadiazole 4 with the methyl enol ether of α-bromo ketones followed by hydrolysis; (ii) reductive amination of γ-ketones 5 and 9 to further reorganized
Diastereoselective cyclopropanation via homochiral ketals. Dioxolane structural effects
作者:Eugene A Mash、Keith A Nelson、Phillip C Heidt
DOI:10.1016/s0040-4039(00)95995-1
日期:1987.1
series of 2-cyclohexen-1-one ketals related to 2-cyclohexen-1-one 1,4-di- O-benzyl-L-threitol ketal but possesing different dioxolane appendages was prepared and subjected to Simmons-Smith cycloproponation. The observed diastereoselectivity decreased when oxygen was present in the appendages. In the absence of appendage oxygen, the sense of the observed diastereoselectivity was found to depend upon dioxolane