Stannatrane

These reagents differ from their tetraalkyl organostannane analogues in that there is no participation of dummy ligands in the transmetalation step, offering selective alkyl transfer in Stille Coupling reactions.

The presence of the tin-nitrogen interaction, albeit weaker than anticipated, led to a few key discoveries: (1) the distortion from ideal trigonal bipyramidal toward monocapped tetrahedron geometry;[7] (2) the lengthening of the apical tin-methyl bond by ~ 0.1 Å (largest known value for any existing tetraorganotin compounds); (3) the observation of unusual hybridization at the apical tin-methyl bond.

A modified synthesis of atrane tricycle utilizes Schwartz's Reagent, triallylamine, and tin(IV) chloride in a one-pot method.

The earliest reported use of carbastannatranes in palladium-catalyzed Stille coupling reactions in 1992 compared the efficiency of methyl stannatrane with tetramethyltin in the presence of aryl bromides and alkenyl iodides.

Related methodology enable selective acyl substitution using enantioenriched stannatranes as an alternative to classical enolate chemistry.

The general structure of a stannatrane reagent, where variants have been synthesized with X=C (carbastannatrane) and X=N (azastannatrane) and R is an alkyl or aryl substituent.
Synthesis of stannatrane chloride and methyl stannatrane by Jurkschat and colleagues.
Stereoscopic representation of methyl stannatrane crystal structure.
(1) Hydrozirconation method for synthesizing stannatrane chloride. (2) Synthesis of lithium carbastannatrane and subsequent mesylate displacement.
(1) Hydrozirconation method for synthesizing stannatrane chloride. (2) Synthesis of lithium carbastannatrane and subsequent mesylate displacement.
A stereoretentive Stille coupling using alkyl carbastannatranes.