Asymmetric intramolecular Heck reaction has been accomplished in the presence of ( R )-BINAP for the synthesis of decalin derivative with good enantioselectivity (Scheme 7).

Scheme 7

3.7.3 Sonogashira Coupling

The C-C cross-coupling reaction of organocopper reagents with electrophiles is a well known method and does not require the presence of transition metals as catalyst. Nevertheless, it is found that palladium can accelerate the reaction. The palladium-catalyzed C-C cross-coupling of in situ generated alkynylcopper reagents with aryl as well as alkenyl halides is known as the Sonogashira Coupling (Scheme 8-9). The reaction takes place smoothly under mild conditions in the presence of catalytic amount of copper(I) iodide and tolerates a variety of functional groups in both coupling partners including hydroxo, carbonyl, amino, acyloxy, acetal, esters, amides etc. Thus, this reaction has been extensively used to the synthesis of many natural products and pharmaceuticals and macromolecules.

Scheme 8

Proposed Mechanism