with several nucleophiles to give multi-substituted cyclobutanes. The reaction of the cyclobutylmagnesium carbenoids with lithium α-sulfonyl carbanions afforded alkylidenecyclobutanes in moderate to good yields. cyclobutane - alkylidenecyclobutane - magnesium carbenoid - cyclobutylmagnesium carbenoid - cyclobutylmagnesium chloride
Synthesis of Spiro[2.2]pentanes and Spiro[2.3]hexanes Employing the Me<sub>3</sub>
Al/CH<sub>2</sub>
I<sub>2</sub>
Reagent
作者:Ilfir R. Ramazanov、Rita N. Kadikova、Tat'yana P. Zosim、Usein M. Dzhemilev、Armin de Meijere
DOI:10.1002/ejoc.201700991
日期:2017.12.22
Substituted alkylidenecyclopropanes reacted with 5 equivalents each of Me3Al and CH2I2 at room temperature in hexane to give 1-mono- and 1,1-disubstituted spiro[2.2]pentanes in high yields. Surprisingly, the same reaction with substituted alkylidenecyclopropanes in CH2Cl2 afforded exclusively 1,1-disubstituted spiro[2.3]hexanes. The transformation of 1,1-diphenylspiro[2.2]pentane into 1,1-diphenylspiro[2
Enantioselective synthesis of 2-alkyl-2-aryl cyclopentanones by asymmetric epoxidation of tetrasubstituted cyclobutylidene olefins and epoxide rearrangement
作者:Yu-Mei Shen、Bin Wang、Yian Shi
DOI:10.1016/j.tetlet.2006.05.175
日期:2006.7
This letter describes a highly enantioselectiveepoxidation of tetrasubstituted benzylidenecyclobutanes using glucose-derived ketone as catalyst and oxone as oxidant. The Et2AlCl promoted rearrangement of the resulting epoxides provides 2-alkyl-2-aryl cyclopentanones with high ees.