Preparation of η1-1,3-dienyl, η1-1,2-dienyl and η3-cyclobutenone complexes via reactions of transition-metal carbonyl containing anions with allenic electrophiles
“…(i) Reactions of the Cyclopentadienyl Molybdenum Tricarbonyl Anion with Allenic Electrophiles. We have previously described many examples of S N 2‘ reactions of cobaloxime and co(salen) anions with allenic electrophiles to yield transition-metal-substituted 1,3-dienes, but in our experience, S N 2 reactions of transition-metal anions with allenic electrophiles have been rare. , Reaction of the CpMo(CO) 3 anion 4 (M = Na) with tosylate 5 initially produced 6 ; however, 6 rapidly underwent further reaction at 25 °C to produce another air-stable yellow complex, which we identified as alkylidene cyclobutanonyl complex ( 9 ). , …”
Section: Resultsmentioning
confidence: 91%
“…Complex 30 , however, could serve as a precursor to 29 via CO loss and could also serve as a precursor to the E isomer ( 28b ) via CO insertion and alkene insertion. However, since 30 was never isolated in large amount from any experiment, it is unlikely to be synthetically useful compared with our other previously reported 1,3-dienyl complexes, ,, and its reaction chemistry was not pursued further.…”
Section: Resultsmentioning
confidence: 99%
“…Cyclopentadienylmolybdenum Dicarbonyl- η 3 -3-methyl-2-methylene-2 E -cyclobuten-1-one (14a) Using Sodium Amalgam. The molybdenum complex 14a was synthesized according to an adaptation of a procedure we have described …”
Section: Methodsmentioning
confidence: 99%
“…In 1992, Green et al reported two examples of complexed cyclobutenone synthesis from the reaction of CpMo(CO) 3 anions with 4-chloro-3-ethyl- and 4-chloro-3-methyl-1,2-butadiene . In 1994, we also independently reported one example of complexed cyclobutenone synthesis from the reaction of the CpMo(CO) 3 anion with 4-tosyl-1,2-butadiene as part of a general survey of reactions of a number of metal carbonyl anions with this electrophile . Last year, we communicated the results of a number of reactions of methyl-substituted allenic electrophiles with the CpMo(CO) 3 anion .…”
Cyclopentadienylmolybdenumtricarbonyl anion reacts with a variety of allenic electrophiles to produce η 3 -2-alkylidene cyclobutanonyl and/or η 3 -butadienyl complexes. The 2-alkylidene cyclobutanone can be synthetically modified, while still complexed to molybdenum, by nucleophilic addition to the carbonyl or via enolate chemistry. The cyclobutanone can then be removed from the metal via oxidative demetalation. Several of the new complexes reported here have been characterized by X-ray crystallography.
“…(i) Reactions of the Cyclopentadienyl Molybdenum Tricarbonyl Anion with Allenic Electrophiles. We have previously described many examples of S N 2‘ reactions of cobaloxime and co(salen) anions with allenic electrophiles to yield transition-metal-substituted 1,3-dienes, but in our experience, S N 2 reactions of transition-metal anions with allenic electrophiles have been rare. , Reaction of the CpMo(CO) 3 anion 4 (M = Na) with tosylate 5 initially produced 6 ; however, 6 rapidly underwent further reaction at 25 °C to produce another air-stable yellow complex, which we identified as alkylidene cyclobutanonyl complex ( 9 ). , …”
Section: Resultsmentioning
confidence: 91%
“…Complex 30 , however, could serve as a precursor to 29 via CO loss and could also serve as a precursor to the E isomer ( 28b ) via CO insertion and alkene insertion. However, since 30 was never isolated in large amount from any experiment, it is unlikely to be synthetically useful compared with our other previously reported 1,3-dienyl complexes, ,, and its reaction chemistry was not pursued further.…”
Section: Resultsmentioning
confidence: 99%
“…Cyclopentadienylmolybdenum Dicarbonyl- η 3 -3-methyl-2-methylene-2 E -cyclobuten-1-one (14a) Using Sodium Amalgam. The molybdenum complex 14a was synthesized according to an adaptation of a procedure we have described …”
Section: Methodsmentioning
confidence: 99%
“…In 1992, Green et al reported two examples of complexed cyclobutenone synthesis from the reaction of CpMo(CO) 3 anions with 4-chloro-3-ethyl- and 4-chloro-3-methyl-1,2-butadiene . In 1994, we also independently reported one example of complexed cyclobutenone synthesis from the reaction of the CpMo(CO) 3 anion with 4-tosyl-1,2-butadiene as part of a general survey of reactions of a number of metal carbonyl anions with this electrophile . Last year, we communicated the results of a number of reactions of methyl-substituted allenic electrophiles with the CpMo(CO) 3 anion .…”
Cyclopentadienylmolybdenumtricarbonyl anion reacts with a variety of allenic electrophiles to produce η 3 -2-alkylidene cyclobutanonyl and/or η 3 -butadienyl complexes. The 2-alkylidene cyclobutanone can be synthetically modified, while still complexed to molybdenum, by nucleophilic addition to the carbonyl or via enolate chemistry. The cyclobutanone can then be removed from the metal via oxidative demetalation. Several of the new complexes reported here have been characterized by X-ray crystallography.
“…Welker and coworkers reacted [132] allene halides and tosylates with the Fp anion. Fp 1 -1,3-dienyl complexes were prepared, characterized, and their reactivity explored (Scheme 73).…”
Section: Fe-c (Sp) Bond Formation (Table 6)mentioning
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