B. Connell Fischer carbenes Chem 206 NHt-Bu 78°cto-40°c 91% [2+1 NHt-Bu [33] Chem. Commun., 1994. 321 OCH3 NH+-Bu 义 Acs,1995,9419 JAcs,1996,695 Chem. Eur. . 1996 88 70:30 25°C,7 egioselectivi 10 times faster than (CO)sCr= 92:8 70% 15/1612/20/993:56PM
B. Connell Fischer Carbenes Chem 206 [4 + 3] Annulation N H NHt-Bu Cr(CO)5 Ph OCH3 N H3CO Et Ph NHt-Bu Et [2 + 1] HN OCH3 Et Ph NHt-Bu [3,3] N H H3CO Et Ph NHt-Bu Barluenga Chem. Commun., 1994, 321. JACS, 1995, 9419. JACS, 1996, 695. Chem. Eur. J., 1996, 88. -78 °C to -40 °C 91% (CO)5Cr OCH3 H3CO (CO)5Cr 104 times faster than methyl acrylate Wulff, JACS, 1990, 4550. Diels-Alder Cycloaddition CH3 H3C 25 °C, 3 h 70% O OCH3 H3CO O CH3 H3C 25 °C, 7 mo 54% 92:8 regioselectivity 70:30 regioselectivity 15/16 12/20/99 3:56 PM
B. Connell Fischer carbenes Chem 206 Die/s-Alder Cycloadditions 25°C,2h 85% Hco 170%C.1h 22% Haco JACs1983,6726 JAcs1990,3642 H3CO r (CH3)2 120°C.48h 25°C,2h H3COW(CO)5 25C,2h 87% H3C ①.A.A HcO (CO)5C 25°C.2h 17/1812/20/993:57PM
B. Connell Fischer Carbenes Chem 206 O Si(CH3)2 O H3CO W(CO)5 H3CO 120 °C, 48 h 25 °C, 2 h Si(CH3)2 O H3CO W(CO)5 H Si(CH3)2 O H3CO O H Wulff JACS 1983, 6726. JACS 1990, 3642. Diels-Alder Cycloadditions CH3 (OC)5Cr H3CO CH3 O H3CO 25 °C, 2 h 85% 170 °C, 1 h 22% Me H3CO Cr(CO)5 Me H3CO O addition of LA causes decomp 100% Diels-Alder Cycloadditions Wulff, JACS, 1990, 3642. Cr(CO) H3CO 5 CH3 (CO) H 5Cr 3CO H3C 25 °C, 2 h 87% 25 °C, 2 h 88% Me H3CO Cr(CO)5 9:1 + Me OCH3 Cr(CO)5 Me H3CO Cr(CO)5 Me OCH3 Cr(CO) + 5 8.5:1.5 17/18 12/20/99 3:57 PM