alpha-Chloro- and alpha-bromoalkyl Grignard reagents 11 and 30 with > 97% ee (enantiomeric excess) were generated by a sulfoxide/magnesium exchange reaction from the enantiomerically and diastereomerically pure sulfoxides 25 and 27. The resulting alpha-haloalkyl Grignard reagents are configurationally stable at -78 degrees C. Racemization sets in at or above -60 degrees C, especially when the solution contains bromide ions. In the absence of halide ions, the configurational stability extends up to -20 degrees C, when chemical decomposition commences.

We have studied 91 patients with SS genotype, 44 children and 47 adults. Excluding the Cameroon and atypical haplotypes, the distribution in the children's sample exhibited 43% Benin, 38% Bantu, and 3% Senegal. In adults, the sample exhibited 46% Benin, 30% Bantu, and 9% Senegal (chi 2: 13.511, 2 df, P = 0.001). When the whole sample of 198 chromosomes (SS, SC, and S/beta thal) is considered, we find that the beta s chromosome is linked 51% to the Benin haplotype, 41% with the Bantu, and 8% with the Senegal. After adjusting for the different frequencies of beta s in Africa, these numbers would predict the port of origin to be 16% from Atlantic West Africa, 37.3% from Central West Africa, and 46% from Bantu-speaking Africa. This is in direct contradiction with the historical record that establishes a higher percentage from Bantu-speaking Africa (55%) and a much lower percentage from Senegal (3.4%). The overall conclusions from these findings is that there is a loss of Bantu haplotypes in sickle cell syndromes in Cuba, particularly among adults, and that there is an excess of Senegal haplotype, also among adults. These differences might reflect the differential survival and severity of the sickle cell disease linked to these haplotypes.

[TiCl3(THF)3] reagiert mit [(ButNLi)2 · SiMe2]2 in Diethylether bei –35 °C unter Redox‐Disproportionierung und Bildung des gelben Titana(IV)‐Oxacyclohexan‐Komplexes [Ti(CH2)4O{Me2Si(NBut)2}]2. Nach der Kristallstrukturanalyse sind die Titanatome über die O‐Atome der Ti(CH2)4O‐Sechsringe, die in der Sesselkonformation vorliegen, zu zentrosymmetrischen Dimeren verknüpft. Zusammen mit den N‐Atomen der chelatisierenden [Me2Si(NBut)2]2–‐Liganden erreichen die Titanatome verzerrt trigonal‐bipyramidale Umgebung. Als Nebenprodukt wird hierbei [TiCl{Me2Si(NBut)2}]3(μ3‐O)(μ3‐Cl) mit clusterähnlichem Aufbau erhalten. Nach der Kristallstrukturanalyse des an der Synthesereaktion beteiligten [Li2(THF)3 · {Me2Si(NBut)2}] sind die beiden Lithiumatome mit beiden N‐Atomen der t‐Butylamid‐Gruppen verbunden und über ein O‐Atom eines der THF‐Moleküle verbrückt.

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