Pt-Catalyzed Pentannulations from In Situ Generated Metallo−Carbenoids Utilizing Propargylic Esters
摘要:
A highly selective and efficient Pt-catalyzed pentannulation reaction beginning from propargylic esters is described. The key to this reaction is the use of a PtCl2(PPh3)2/PhIO catalyst combination that allows the in situ generation of Pt-carbenoid intermediates, which lead to good yields (61-84%) of the desired pentannulated compounds.
Pt-Catalyzed Tandem Epoxide Fragmentation/Pentannulation of Propargylic Esters
作者:Brian G. Pujanauski、B. A. Bhanu Prasad、Richmond Sarpong
DOI:10.1021/ja061549m
日期:2006.5.1
A Pt-catalyzed pentannulation of propargylic esters containing an epoxide moiety has been developed. The present transformation achieves the formation of cyclopentenone products as single diastereomers in good yields. The observed products likely form from pyran intermediates that undergo an oxa-6pi electrocyclic ring opening to a functionalized dienone, followed by ring closure with an accompanying acyl shift.