Vinylaluminum Addition to Sulfinimines (<i>N</i>-Sulfinyl Imines). Asymmetric Synthesis of <i>anti</i>-α-Alkyl β-Amino Esters

Addition of vinylaluminum NMO reagents to N-(p-toluenesufinyl)- and N-(2-methypropanesulfinyl)-derived sulfinimines gives N-sulfinyl aza-Morita−Baylis−Hillman products (dr = 7:1 to 12:1) that result from addition of the reagent from the least hindered direction. Hydrogenation of the aza-MBH adducts with a Rh(I) catalyst affords anti-α-substituted N-sulfinyl-β-amino esters in good yield and high dr (10:1 to 21:1)

Enantioselective Synthesis of Cocaine C-1 Analogues using Sulfinimines (<i>N</i>-Sulfinyl Imines)

The first examples of cocaine analogues having substituents (methyl, ethyl, <i>n</i>-propyl, <i>n</i>-pentyl, and phenyl) at the C-1 position of the cocaine tropane skeleton were prepared by heating sulfinimine-derived α,β-unsaturated pyrrolidine nitrones. In the presence of the Lewis acid Al­(O<i>^t</i>Bu)₃ the nitrones undergo an intramolecular [3 + 2] cycloaddition to give tricyclic isoxazolidines that were transformed in three steps to the cocaine analogues. In the absence of the Lewis acid, lactams were formed resulting from rearrangement of the nitrone to an oxaziridine. A novel Pd- and base-promoted rearrangement of methanesulfonate salts of isoxazolidine to bridge bicyclic[4.2.1]­isoxazolidines was discovered

Enantioselective Synthesis of Cocaine C-1 Analogues using Sulfinimines (<i>N</i>-Sulfinyl Imines)

The first examples of cocaine analogues having substituents (methyl, ethyl, <i>n</i>-propyl, <i>n</i>-pentyl, and phenyl) at the C-1 position of the cocaine tropane skeleton were prepared by heating sulfinimine-derived α,β-unsaturated pyrrolidine nitrones. In the presence of the Lewis acid Al­(O<i>^t</i>Bu)₃ the nitrones undergo an intramolecular [3 + 2] cycloaddition to give tricyclic isoxazolidines that were transformed in three steps to the cocaine analogues. In the absence of the Lewis acid, lactams were formed resulting from rearrangement of the nitrone to an oxaziridine. A novel Pd- and base-promoted rearrangement of methanesulfonate salts of isoxazolidine to bridge bicyclic[4.2.1]­isoxazolidines was discovered

Enantioselective Synthesis of Cocaine C-1 Analogues using Sulfinimines (<i>N</i>-Sulfinyl Imines)

The first examples of cocaine analogues having substituents (methyl, ethyl, n-propyl, n-pentyl, and phenyl) at the C-1 position of the cocaine tropane skeleton were prepared by heating sulfinimine-derived α,β-unsaturated pyrrolidine nitrones. In the presence of the Lewis acid Al­(OtBu)3 the nitrones undergo an intramolecular [3 + 2] cycloaddition to give tricyclic isoxazolidines that were transformed in three steps to the cocaine analogues. In the absence of the Lewis acid, lactams were formed resulting from rearrangement of the nitrone to an oxaziridine. A novel Pd- and base-promoted rearrangement of methanesulfonate salts of isoxazolidine to bridge bicyclic[4.2.1]­isoxazolidines was discovered

Enantioselective Synthesis of Cocaine C-1 Analogues using Sulfinimines (<i>N</i>-Sulfinyl Imines)

The first examples of cocaine analogues having substituents (methyl, ethyl, <i>n</i>-propyl, <i>n</i>-pentyl, and phenyl) at the C-1 position of the cocaine tropane skeleton were prepared by heating sulfinimine-derived α,β-unsaturated pyrrolidine nitrones. In the presence of the Lewis acid Al­(O<i>^t</i>Bu)₃ the nitrones undergo an intramolecular [3 + 2] cycloaddition to give tricyclic isoxazolidines that were transformed in three steps to the cocaine analogues. In the absence of the Lewis acid, lactams were formed resulting from rearrangement of the nitrone to an oxaziridine. A novel Pd- and base-promoted rearrangement of methanesulfonate salts of isoxazolidine to bridge bicyclic[4.2.1]­isoxazolidines was discovered

Enantioselective Synthesis of Cocaine C-1 Analogues using Sulfinimines (<i>N</i>-Sulfinyl Imines)

The first examples of cocaine analogues having substituents (methyl, ethyl, <i>n</i>-propyl, <i>n</i>-pentyl, and phenyl) at the C-1 position of the cocaine tropane skeleton were prepared by heating sulfinimine-derived α,β-unsaturated pyrrolidine nitrones. In the presence of the Lewis acid Al­(O<i>^t</i>Bu)₃ the nitrones undergo an intramolecular [3 + 2] cycloaddition to give tricyclic isoxazolidines that were transformed in three steps to the cocaine analogues. In the absence of the Lewis acid, lactams were formed resulting from rearrangement of the nitrone to an oxaziridine. A novel Pd- and base-promoted rearrangement of methanesulfonate salts of isoxazolidine to bridge bicyclic[4.2.1]­isoxazolidines was discovered

Enantioselective Synthesis of Cocaine C-1 Analogues using Sulfinimines (<i>N</i>-Sulfinyl Imines)

The first examples of cocaine analogues having substituents (methyl, ethyl, <i>n</i>-propyl, <i>n</i>-pentyl, and phenyl) at the C-1 position of the cocaine tropane skeleton were prepared by heating sulfinimine-derived α,β-unsaturated pyrrolidine nitrones. In the presence of the Lewis acid Al­(O<i>^t</i>Bu)₃ the nitrones undergo an intramolecular [3 + 2] cycloaddition to give tricyclic isoxazolidines that were transformed in three steps to the cocaine analogues. In the absence of the Lewis acid, lactams were formed resulting from rearrangement of the nitrone to an oxaziridine. A novel Pd- and base-promoted rearrangement of methanesulfonate salts of isoxazolidine to bridge bicyclic[4.2.1]­isoxazolidines was discovered

Enantioselective Synthesis of Cocaine C-1 Analogues using Sulfinimines (<i>N</i>-Sulfinyl Imines)

The first examples of cocaine analogues having substituents (methyl, ethyl, <i>n</i>-propyl, <i>n</i>-pentyl, and phenyl) at the C-1 position of the cocaine tropane skeleton were prepared by heating sulfinimine-derived α,β-unsaturated pyrrolidine nitrones. In the presence of the Lewis acid Al­(O<i>^t</i>Bu)₃ the nitrones undergo an intramolecular [3 + 2] cycloaddition to give tricyclic isoxazolidines that were transformed in three steps to the cocaine analogues. In the absence of the Lewis acid, lactams were formed resulting from rearrangement of the nitrone to an oxaziridine. A novel Pd- and base-promoted rearrangement of methanesulfonate salts of isoxazolidine to bridge bicyclic[4.2.1]­isoxazolidines was discovered