Cross-coupling reactions with organic halides

Single crystal X-ray analysis of the ethynyl-l,5-azastibocine 5a showed the presence of intramolecular Sb---N interaction which should be responsible for the reactivity enhancement of the ethynyl-l,5-azastibocines in Pd-catalyzed cross-coupling reactions with organic halides (see Section 14.18.11). The distance between the antimony and nitrogen atoms (2.538(4) A) corresponds to 68% of the sum of the van der Waals radii of both elements (3.74 A). In the crystal central antimony atom exhibited a pseudo-trigonal-bipyramidal structure <2003TL8589>. 

Although alkylmagnesium, -zinc, -tin, and -aluminium reagents have been successfully used for the cross-coupling reaction with organic halides [1], the reaction of alkylborane... 

Although the cross-coupling reaction with organic halides generally requires the assistance of bases, allylic phenoxide and cinnamyl acetate react with 1-alkenylborates under neutral conditions to yield 75% and 12%, respectively, of the corresponding 1,4-dienes (Scheme 2-21) [45, 54]. Thus, the jT -(allylphenoxo)- and r-... 

Palladium-Catalyzed Cross-Coupling Reaction with Organic Halides. . 148... 

A large number of fluorous tin reagents for use in palladium-catalyzed Stille cross-coupling reactions with organic halides or triflates have been developed. Reaction times can be reduced to just a few minutes when conducted with microwave heating. Three-phase extraction between water (top), dichloromethane (middle), and perfluorohexanes (FC-72) (bottom) allow the coupled product to be isolated from the dichloromethane and the resulting fluorinated tin chloride to be recovered from the FC-72 phase and recycled (Scheme 5.8.8). 

Organoboranes have many advantages as the organometallic component (R M) for the Pd-catalyzed carbonylative cross-coupling reaction with organic halides (RX). They can be prepared in many ways and are compatible with a variety of functional groups of synthetic importance. Most boronic acids and esters are stable to air and moisture. 

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