A number of C 2 -symmetrical geminal bis-(sulfoximine)s have been prepared for the first time and used as ligands in boron-mediated reductions of acetophenone and copper complex-catalyzed 1,4-additions of diethylzinc to 2-cyclohexenone. The copper complex of bis(sulfoximine) 46 was found to be highly active in this type of reaction, furnishing the addition product in nearly quantitative yield even at À 90 8C. From the reaction of bis(sulfoximine) 42 with Cu(OTf) 2 a copper complex was isolated and characterized by X-ray structural analysis. A mixture of SES-Cl and NaN 3 in acetonitrile was found to behave like SES-N 3 in FeCl 2 -mediated iminations of sulfoxides, affording the corresponding sulfoximines with complete retention of the sulfur configuration.

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A new original strategy for the synthesis of axially and helically chiral bidentate diphosphane ligands featuring a rigid triangulanyl backbone has been elaborated and executed for several representative enantiomerically pure ligands. Thus,(1R,3S,4S)‐1,4‐bis[(diphenylphosphanyl)methyl]spiro[2.2]pentane [(1R,3S,4S)‐24·(BH3)2], [(1R,3R,4S)‐4‐(diphenylphosphanyl)methylspiro[2.2]pentan‐1‐yl]diphenylphosphane [(1R,3R,4S)‐27·(BH3)2], [(1R,3R,4S,5R)‐5‐(diphenylphosphanyl)methyldispiro[2.0.2.1]heptan‐1‐yl]diphenylphosphane [(1R,3R,4S,5R)‐30·(BH3)2], (1S,3S,4S)‐1,4‐bis(diphenylphosphanyl)spiropentane [(1R,3S,4S)‐35·(BH3)2], (1S,3S,4S)‐1,4‐bis(diphenylphosphanyl)spiropentane [(1S,3S,4S)‐35·(BH3)2], (1S,3S,4S)‐1,4‐bis(diphenylphosphanyl)spiropentane [(1R,3R,4S)‐35·(BH3)2], and (1R,3R,4R,5R)‐1,5‐bis(diphenylphosphanyl)dispiro[2.0.2.1]heptane [(1R,3R,4R,5R)‐36·(BH3)2] with a spiropentyl and a dispiro[2.0.2.1]heptyl moiety, respectively, have been prepared as bishydroborane complexes applying repetitively the same set of standard synthetic operations, starting from [(1S,3R)‐4‐methylenespiropent‐1‐yl]methyl acetate [(1S,3R)‐7], (4,4‐dibromospiropent‐1‐yl)methanols [(1S,3R)‐8 and (1R,3S)‐8] and (dibromodispiro[2.0.2.1]heptyl)methanols (1R,3S,4R)‐9, (1S,3R,4S)‐9 and (1S,3R,4R)‐9 in 4–7 steps. The relative configurations of all important intermediates as well as the absolute configurations of the key intermediates and most final products were established by X‐ray crystal structure analyses.