Organoborane reagents

When vinylboronic acids are used as reactants, bases, especially Tl(OH)3, can accelerate the reaction.143 Scheme 8.11 gives a number of examples of coupling using organoborane reagents. 

In addition, monoterpenes can provide some useful chiral reagents, such as the pinene-based organoborane reagents for chiral reductions, which have been reviewed extensively.42 Camphor-derived organic acids such as camphenesulfonic acid can be used for the resolution of racemic bases and is a common practice in industry (Chapter 6). 

M. M. Midland, Asymmetric Reduction with Organoborane Reagents, Chem. Rev. 1989, 89, 1553. 

E. Block, Olefin synthesis via deoxygenation of vicinal diols, Org. React. (N.Y.) 1984, 30, 457. M. M. Midland, Asymmetric reduction with organoborane reagents, Chem. Rev. 1989,89, 1553. H. C. Brown and P. V. Ramachandran, Asymmetric reduction with chiral organoboranes based... 

Novel Silyl-mediated 10-TMS-9-BBD Organoborane Reagents for Asymmetric Synthesis... 

Very recently, Kakiuchi reported on the ruthenium-catalyzed arylation of C-H bonds using organoborane reagents. The reaction of aromatic ketones with arylboro-nates using a ruthenium catalyst resulted in the production of arylated aromatic ketones (Eq. 9.36) [50], This arylation reaction using arylboronates can be applied to a variety of aromatic ketones and arylboronates. The authors proposed that this reaction involves the oxidative addition of a C-H bond to a Ru(0) species. 

In the first step proceeds an oxidative addition of the aryl halide to a low-coordination Pd(0) species, usually a Pd(0) diphosphine complex. The halide in the n-aryl Pd(II) species is substituted by the aryl group of the organoboran reagent by trans-... 

Scheme 1.9 Cross-coupling of a secondary alkyl halide with an organoborane reagent catalyzed by NiBrj-diglyme.

The growing need for structurally complex compounds labeled with stable and radioisotopes will continue to challenge organic chemists. It is clear that organoborane reagents will play an ever-... 

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