Ligand dimethyltin derivatives

Other investigators (10) have reported ligand exchange effects on the tin-proton coupling constants (Jsii-c-h) for dimethyltin derivatives. We found that in the dibenzyltin system (Table I) the coupling constant increased as the number of chlorines on tin increased. We found also... 

The syntheses of chiral C2-symmetric methylene-bis(oxazolines) and bi-oxazolines of type 6 and 8 are summarized in Schemes 10 and 11 [25]. Using the well-established three-step sequence - amide formation, conversion to the bis(2-chloroalkyl)amide, and subsequent base-induced cyclization [26] - various derivatives were prepared in good overall yields. Alternatively, these ligands may be synthesized in one step from the corresponding amino alcohols and readily available bis-imidates derived from malonate or oxalate [25, 27] or, as described by Masamune et al [28], by amide formation with diethyl malonate and subsequent reaction with dimethyltin dichloride, or by metal-catalyzed condensation of amino alcohols with nitriles [29]. 

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