New strategy for the stereoselective synthesis of fluorinated beta-amino acids.

Racemic and chiral nonracemic alpha-substituted and alpha-unsubstituted beta-fluoroalkyl beta-amino acid derivatives 6 and 9 have been synthesized in two steps starting from fluorinated imidoyl chlorides 1 and ester enolates. This approach is based on the chemical reduction of previously obtained gamma-fluorinated beta-enamino esters 4 by using ZnI(2)/NaBH(4) in a nonchelated aprotic medium (dry CH(2)Cl(2)) as the reducing agent. A metal-chelated six-membered model has been suggested to explain the stereochemical outcome of the reduction reaction.

Gold(I) Complexes with N-Donor Ligands. 2.(1) Reactions of Ammonium Salts with [Au(acac-kappaC(2))(PR(3))] To Give [Au(NH(3))L](+), [(AuL)(2)(&mgr;(2)-NH(2))](+), [(AuL)(4)(&mgr;(4)-N)](+), or [(AuL)(3)(&mgr;(3)-O)](+). A New and Facile Synthesis of [Au(NH(3))(2)](+) Salts. Crystal Structure of [{AuP(C(6)H(4)OMe-4)(3)}(3)(&mgr;(3)-O)]CF(3)SO(3).

The complexes [Au(acac-kappaC(2))(PR(3))] (acac = acetylacetonate, R = Ph, C(6)H(4)OMe-4) react with (NH(4))ClO(4) to give amminegold(I), [Au(NH(3))(PR(3))]ClO(4), amidogold(I), [(AuPR(3))(2)(&mgr;(2)-NH(2))]ClO(4), or nitridogold(I), [(AuPR(3))(4)(&mgr;(4)-N)]ClO(4), complexes, depending on the reaction conditions. Similarly, [Au(acac-kappaC(2))(PPh(3))] reacts with (NH(3)R')OTf (OTf = CF(3)SO(3)) (1:1) or with [H(3)N(CH(2))(2)NH(2)]OTf (1:1) to give (amine)gold(I) complexes [Au(NH(2)R')(PPh(3))]OTf (R' = Me, C(6)H(4)NO(2)-4) or [(AuPPh(3))(2){&mgr;(2)-H(2)N(CH(2))(2)NH(2)}](OTf)(2), respectively. The ammonium salts (NH(2)R'(2))OTf (R' = Et, Ph) react with [Au(acac-kappaC(2))(PR(3))] (R = Ph, C(6)H(4)OMe-4) (1:2) to give, after hydrolysis, the oxonium salts [(AuPR(3))(3)(&mgr;(3)-O)]OTf (R = Ph, C(6)H(4)OMe-4).

Platinum-Assisted Addition of Carbonyl-Stabilized Phosphorus Ylides to Pentafluorobenzonitrile and Acetonitrile To Give Platinum(II) Complexes Containing Iminophosphorane and/or N-Bonded beta-Imino Phosphorus Ylide Ligands. Crystal and Molecular Structures of trans-[PtCl(2){E-NH=C(C(6)F(5))C(=PPh(3))C(O)Me}(2)] and trans-[PtCl(2){E-N(=PPh(3))C(C(6)F(5))=CHCO(2)Et}{E-NH=C(C(6)F(5))C(=PPh(3))CO(2)Et}].

PtCl(2) reacts with C(6)F(5)CN to give trans-[PtCl(2)(NCC(6)F(5))(2)] (1) which, in turn, reacts with carbonyl-stabilized phosphorus ylides Ph(3)P=CHR [R = C(O)Me, CO(2)Et] to give trans-[PtCl(2){NH=C(C(6)F(5))C(=PPh(3))CO(2)Et}{NCC(6)F(5)}] (2a), trans-[PtCl(2){NH=C(C(6)F(5))C(=PPh(3))CO(2)Et}(2)] (3a), trans-[PtCl(2){E-NH=C(C(6)F(5))C(=PPh(3))C(O)Me}(2)] (3b) or trans-[PtCl(2){E-N(=PPh(3))C(C(6)F(5))=CHCO(2)Et}{E-NH=C(C(6)F(5))C(=PPh(3))CO(2)Et}] (4), depending on the reaction conditions. Similarly, Ph(3)P=CHCO(2)Me reacts with trans-[PtCl(2)(NCMe)(2)] to give trans-[PtCl(2){NH=CMeC(=PPh(3))CO(2)Me}(NCMe)] (2b). Complex 3b.