Cycloadditions and annulations of transition metal carbene complexes

Electronic Structure and Reactivity of Metal Carbenes

“…Because of the strongly electron-withdrawing character of the Cr(CO) 5 unit, the reaction with alkynes to hydroquinone and phenol derivatives [35][36][37] (Dötz reaction) is possible according to Scheme 6 (see also Chap. 4 "Chromiumtemplated Benzannulation Reactions").…”

Metal-Assisted Cycloaddition Reactions in Organotransition Metal Chemistry

“…Several competent collecting and reviewing articles with many leading references have appeared. 474,478,[849][850][851] Scheme 77 shows some of the more important intermediates along the reaction coordinate toward the product 535. The reaction is very complex, and depending on the reaction conditions and the substituents in the starting components, the product mixture may, besides hydroquinone derived complexes, e.g.…”

The Dötz Benzannulation Reaction: A Booming Methodology for Natural Product Synthesis

“…Daunomycinone 27 and 11‐deoxydaunomycinone 33 are two most widely studied compounds that have been produced via the Dötz benzannulation reaction (Scheme ) . As can be seen from Scheme , simultaneously two separate Dötz benzannulation approaches were introduced in constructing the B‐ring of daunomycinone 27 and 11‐deoxydaunomycinone 33 .…”

“…Next, these compounds ( 23 and 26 ) yielded the desired natural product 27 after several steps. On the other hand, the aryl‐carbene complex 29 was used with two different alkynes 28 and 31 to afford naphthol derivatives 30 and 32 respectively, which were further transformed into the desired product 33 (Scheme ) …”