ChemInform Abstract: Palladium‐Catalyzed Additions of Terminal Alkynes to Acceptor Alkynes.

Abstract

Palladium-Catalyzed Additions of Terminal Alkynes to AcceptorAlkynes.-In the presence of a catalytic amount of Pd(O-Ac)2 and an electron-rich sterically encumbered ligand such as P(Dmp)3 the C-H bond of a terminal alkyne can be added to either terminal alkynes (self-coupling) or activated internal alkynes (cross-coupling) as is demonstrated for the examples (II) and (V). The internal alkynes bear functional groups such as ester, sulfone and ketone. In these reactions also 1:2 adducts can be obtained. Product (VII) serves as useful precursor to β-keto esters. Application of this method is shown in an iterative sequence starting from (IX) to produce the novel conformationally rigid retinoid analogue (XII). -(TROST, B. M.; SORUM, M. T.; CHAN, C.; HARMS, A. E.; RUEHTER, G.; J. Am. Chem. Soc. 119 (1997) 4, 698-708; Dep. Chem., Stanford Univ., Stanford, CA 94305, USA; EN)