Long Chain Dicationic Phase Transfer Catalysts in the Condensation Reactions of Aromatic Aldehydes in Water Under Ultrasonic Effect
作者:Ilker Esen、Cigdem Yolacan、Feray Aydogan
DOI:10.5012/bkcs.2010.31.8.2289
日期:2010.8.20
Long chain dicationic ammoniumsalts were used successfully as phase transfer catalyst in the condensation reactions of aromatic aldehydes in water under ultrasonic irradiation for the first time. The quaternary salt having longer distance between the cation centers was more effective than the mono- and dicationic ones having short chain.
Controlling the Molecular Topology of Vinylogous Iminium Ions by Logical Substrate Design: Highly Regio- and Stereoselective Aminocatalytic 1,6-Addition to Linear 2,4-Dienals
about topologycontrol: The title reaction yields valuable tetrahydrofuran spirooxindoles (see scheme; TMS=trimethylsilyl), and exemplifies a rare asymmetric 1,6‐addition to linear 2,4‐dienals proceeding with high δ‐site‐ and stereoselectivity. A steering group at the β‐dienal position ensured molecular preorganization of the catalytically active vinylogousiminiumion intermediate for highly predictable
A thiophene, furan or tetrahydrofuran triazolyl derivative having the general formula (I) or (II) :
and stereoisomers thereof, wherein R¹ is tertiary butyl, which may be optionally substituted with one or more halogen atoms; R² is the group :
-(CH₂)n-Z
or -CH=CH-X
or -C≡C-Z
where n is an integer from 0 to 3 and Z is an optionally substituted thiophene, furan, or tetrahydrofuran ring; and X is an optionally substituted thiophene or tetrahydrofuran ring; and R³ is hydrogen or an alkyl group containing from 1 to 4 carbon atoms; and salts, esters and metal complexes of the compound of formula (I) and (II) wherein R³ is hydrogen.