Asymmetric reactions with camphorseleno chiral auxiliaries

This Thesis describes a variety of asymmetric reactions with a series of camphorseleno chiral auxiliaries derived from di ((1R)-endo-3-camphoryl) diselenide and C(2) modified analogues.; The asymmetric oxidations of camphor-derived methyl selenides proceeded with high diastereoselectivities (up to 97% diastereomeric excess (d.e.)). The asymmetric (2,3) sigmatropic rearrangements of camphor-derived neryl and geranyl selenoxides afforded excesses of licareol or coriandrol in 4-34% enantiomeric excesses (e.e.'s). Double differentiation was observed when chiral oxaziridines were used to generate the required selenoxides. Interestingly, the absolute stereochemistry of the products was controlled by the type of chiral auxiliary, and not by the E,Z-geometry of the allylic selenide or the configuration of the oxidant. Poor enantioselectivities (2-19% e.e.'s) were observed in asymmetric selenoxide eliminations of vinyl selenides to chiral allenes.; Moderate to high facial selectivities (47-90% d.e.) were obtained from asymmetric methoxyselenenylations using camphor-derived selenenyl chlorides and triflates. Cyclofunctionalization of 4-pentenamide under neutral conditions resulted in selenenyl chloride 1,2-addition in 90% d.e. The corresponding 4-(camphorselenomethyl)-butyrolactone and 4-(camphorseleno)-3-hydroxypentanenitrile were formed under acidic or basic conditions, respectively, with excellent d.e.'s (90-97%) via an imminium cation intermediate. Cyclofunctionalization of methyl N-(4-pentenyl)carbamate afforded the corresponding {dollar}gamma{dollar}-lactam with moderate stereoselectivity (44% e.e.). Selenenyl azide additions to alkenes with camphor-derived diselenides provided the corresponding 1,2-adducts in good yields, but poor d.e.'s (4-37%).