Tributyltin hydride—Triethylborane

I. Shibata, T. Suzuki, A. Baba, and H. Matsuda, J.C.S. Chem. Comm., 882 (1988). Tributyltin hydride-Triethylborane. 

This unusual reverse reactivity does not follow the usual course of 2,6-dihalopurine derivatives such as 2,6-dichloro and 2,6-dibromopurine, where the product of NH3 treatment is the 6-amino-2-halopurine. The 2-amino-6-chloro (48) and 6-anrino-2-fluoro (49) compounds could also be converted to their corresponding dideoxy (52 and 53) and unsaturated derivative (56 and 57) using tributyltin hydride/triethylborane and hydrogen peroxide/ cat. pyridine, respectively, followed by deprotection. 

The condensation of thymine, uracil and cytosine with 30 went smoothly to give the corresponding 2 -phenylseleno nucleosides (58, 59 and 60) (Scheme 13). For the cytidine derivative 60, it was found that the use of A/ -acetyl cytosine gave the best results in regard to yield and ease of purification. These compounds underwent smooth conversion to the dideoxy analogues ddT (63), ddU (64) and ddC (67) on treatment with tributyltin hydride/triethylborane at room temperature, followed by deprotection, or to the unsaturated analogues d4T (70) and d4U (71) on treatment with hydrogen peroxide/cat. pyridine and desilylation. 

Deoxygenation of primary and secondary alcohols.1 This deoxygenation has been effected by reduction of the thiocarbonyl esters with tributyltin hydride and AIBN as the radial initiator (11, 550). A newer, milder method uses diphenylsilane in a radical chain reaction initiated by triethylborane and air. Even secondary thiono-carbonates, particularly those derived from 4-fluorophenol, are deoxygenated at 25°. 

Tributyltin hydride adds to terminal acetylenes in the presence of triethylborane to give mixtures of E)- and (Z)- alkenes, in which the tin atom is attached to C(l), e.g. equation 40215,216 reverse regiochemistry is observed in the reaction of tributylstannane with terminal acetylenes in the presence of rhodium complexes, e.g. [RhCl (1,5-cyclooctadiene)]2, to yield exclusively the adducts 297. ... 

Vicinal allylsilyloxydihaloalkanes 69 have been demonstrated to undergo radical cyclisation with tributyltin hydride in the presence of catalytic amounts of triethylborane to afford the seven-membered silyl ethers 70 <97CSJ2255>, and RCM has been used to form the unsaturated analogues 71 <97TL4757>. 

The reaction was carried out by mixing a solution of glutarate 9 with 8 and Sc(OTf)3 in diethyl ether saturated with air with a solution of tributyltin hydride containing triethylborane under argon in the microreactor on-line coupled to the ESI ion source (Figure 5.9). The reacting solution was fed continuously into the mass spectrometer. 

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