Ruthenium-catalysed reductive cleavage reactions of allylic carboxylates and carbonates with formic acid and triethylamine to give olefins were explored. As an application of the ruthenium-catalysed processes, a new synthetic route to α-hydroxy acids has been discovered. The reductive cleavage of allylic esters is considered to proceed through π-allylruthenium intermediates.
Synthese von ?-Acetyl-?-methylenpolyencarbons�ureestern
作者:Hartmut Laatsch、Alke Pudleiner
DOI:10.1002/prac.19943360806
日期:——
The alpha-methylenpolyene carboxylic acids 1 and 2 are highly active against Gram-positive bacteria. If this activity arises from an interference with the cell membranes, then an abrupt change in biological properties is to be expected with growing chain length of simple model compounds. To make these tests possible, we describe here the synthesis of a series of homologue esters of type 40. Their synthesis was achieved by Wittig reactions of polyene alpha,omega-dialdehydes 6 with acetyl-methylentriphenylphosphoran 5a and the protected carboxymethylmethylen triphenylphosphonium salt 8.
Synthesis and reactions of derivatives of 1,7-dioxaspiro[5.5]undec-2-en-4-one
作者:Anthony G. M. Barrett、Robin A. E. Carr、Mark A. W. Finch、Jean Claude Florent、Geoffrey Richardson、Nigel D. A. Walshe