Organic Syntheses via Transition Metal Complexes. 72. (2-(Acyloxy)ethenyl)carbene Complexes by Michael Addition of Carboxylic Acids to Alkynylcarbene Complexes (M = Cr, W). (2-(Acyloxy)ethenyl)ketene Imines by Ligand Disengagement with Isocyanide
作者:Rudolf Aumann、Beate Jasper、Mechtild Laege、Bernt Krebs
DOI:10.1021/om00021a025
日期:1994.9
(2-(Acyloxy)ethenyl)carbene complexes (CO)(5)M=C(OEt)-CH=C(OCOR)Ph [(Z)-5] (M = Cr, W; R = Ph, p-Me(2)NC(6)H(4), CH3, cC(7)H(7)CH(2), PhCH=CPh, Me(2)C=CH, 1,4-C6H4) are obtained by the addition of carboxylic acids R-CO2H (4) to alkynylcarbene complexes (CO)(5)M=C(OEt)-C=CPh (1) (M = Cr, W) in the presence of Et(3)N at 20 degrees C in 71-78% isolated yields. The reaction is regio- and stereochemically uniform. (Z)-5g (R=PhCH=CPh), C31H22O8W, was characterized by X-ray diffraction. It crystallizes in space group Pi with cell parameters a 10.381(6) Angstrom, b 11.444(6) Angstrom, c 13.509(7) Angstrom, alpha = 107.84(4)degrees, beta = 91.54(4)degrees, gamma = 108.49(4)degrees, Z = 2, R(1) = 0.0354, and wR(2) = 0.0811. Ligand disengagement from (Z)-5 with tert-butyl isocyanide (8b) at 20 degrees C results in the formation of [2-(acyloxy)ethenyl]ketene imines t-BuN=C=C(OEt)-CH=C(OCOR)Ph [(Z)-11] (> 95% yields).
(2-(酯基氧)乙烯基)卡宾复合物 (CO)₅M=C(OEt)-CH=C(OCOR)Ph [(Z)-5] (M = Cr, W; R = Ph, p-Me₂NC₆H₄, CH₃, iC₇H₇CH₂, PhCH=CPh, Me₂C=CH, 1,4-C₆H₄) 是通过在 20°C 下在 Et₃N 的存在下,将羧酸 R-CO₂H (4) 加入到炔基卡宾复合物 (CO)₅M=C(OEt)-C=CPh (1) (M = Cr, W) 中,以 71-78% 的收率获得的。该反应在区域化学和立体化学上是均匀的。(Z)-5g (R=PhCH=CPh),C₃₁H₂₂O₈W,通过 X 射线衍射进行了表征。它在空间群 P₁中结晶,晶胞参数 a = 10.381(6) Å,b = 11.444(6) Å,c = 13.509(7) Å,α = 107.84(4)°,β = 91.54(4)°,γ = 108.49(4)°,Z = 2,R(1) = 0.0354,wR(2) = 0.0811。(Z)-5 与叔丁基异氰化物 (8b) 在 20°C 下分离配体,生成 [2-(酯基氧)乙烯基]酮烯酰席夫碱 t-BuN=C=C(OEt)-CH=C(OCOR)Ph [(Z)-11] (> 95% 收率)。