Activation of prop-2-yn-1-ols by metal carbonyls: Synthesis of (alkoxyalkenylcarbene)- and (aminoalkenylcarbene)chromium and -tungsten complexes

Article abstract of DOI:10.1021/om00004a054

Fischer type methoxyalkenylcarbene complexes (CO)₅M=C(OMe)(CH=CRR′) have been prepared in one step by photolysis of M(CO)₆ [M = Cr, W] in tetrahydrofuran-methanol, in the presence of prop-2-yn-1-ol derivatives HC≡CC(OH)(R)(R′) [R, R′ = Me; R = H, R′ = Me, Ph, C₆H₄-p-NMe₂]. Photolysis of a tetrahydrofuran-methanol solution of M(CO)₆ with HC≡CC(OH)(H){(CH=CH)_nCH=CRR′} [n = 0 R, R′ = Me; R = H, R′ = H, Me, Ph, C₆H₄-p-NMe₂, C₅H₁₁; n = 1 R = H, R′ = Me] provides the new dienyl- and trienylcarbene complexes (CO)₅W=C(OMe)(CH=CHCH=CRR′) and (CO)₅M=C(OMe)(CH=CHCH=CHCH=CHMe) in 30-70% yields. Alkoxyalkenylcarbene complexes (CO)₅M=C(OCH₂Z)(CH=CRR′) are prepared analogously by using other primary alcohols ZCH₂OH [Z = CH₂CH(Me)(Et), CH₂-CH₂C≡CMe, CH₂CH₂CH=CH₂, CH₂CH₂C(Me)=CH₂. [(Alkenyloxy)alkenylcarbene]tungsten complexes undergo smooth thermal intramolecular cyclopropanation reactions leading to 1-alkenyl-2-oxabicyclo[3.1.0]hexane compounds. Finally, a series of aminodienylcarbene complexes (CO)₅W=C(NHR′)(CH=CHCH=CHR) [R = Ph, C₅H₁₁; R′ = CHMe₂, CMe₃, CH₂-CH=CH₂, CH₂CHMe₂] have been synthesized by aminolysis of the corresponding methoxydienyl carbenes.