Lewis Base Effects in the Baylis−Hillman Reaction of Imines with Methyl Vinyl Ketone

Recent extensions of the Morita–Baylis–Hillman reaction

“…Whereas the use of PBu 3 provides a mixture of pyrroline 19 and pyrrole 20 resulting from the dehydration and desulfinylation of the tosyl group in the basic reaction medium (Scheme 21). 25 We confirmed that 19 and 20 were formed independently during the reaction because 19 cannot be transformed into 20 under these conditions. It is believed that the difference in nucleophilicity between PPh 3 and PBu 3 is the key factor for the different reaction products.…”

Recent extensions of the Morita–Baylis–Hillman reaction

“…Whereas the use of PBu 3 provides a mixture of pyrroline 19 and pyrrole 20 resulting from the dehydration and desulfinylation of the tosyl group in the basic reaction medium (Scheme 21). 25 We confirmed that 19 and 20 were formed independently during the reaction because 19 cannot be transformed into 20 under these conditions. It is believed that the difference in nucleophilicity between PPh 3 and PBu 3 is the key factor for the different reaction products.…”

Synthesis of Side-Chain Functional Polyesters via Baylis–Hillman Polymerization

“…The use of these catalysts for the polymerization of 1 and 2 , however, was not found to result in polymers with molecular weights higher than those obtained via the DABCO catalyzed polymerization (see procedures 2 and 3 in Table ). Similarly, replacing DABCO by 4-(dimethylamino)pyridine (DMAP) or triphenylphosphine , also did not to result in polymers with increased molecular weights (Table , procedures 4 and 5). For procedures 3–5, Table only lists a single data point.…”

Synthesis, Molecular Structure, and Catalytic Evaluation of Centrostereogenic Ferrocenophane Phosphines

“…The reaction of N -tosylimine 8a with 2 mol equiv of the ketone in the presence of 10 mol % of chiral phosphine 2a performed at room temperature for 5 h afforded 9a in 27% yield and with 97% ee (Table , entry 1). Unfortunately, the reaction was only poorly chemoselective, affording various side products, among which the product of double addition 10 and heterocycles 11 and 12 (Scheme ) were identified by NMR analysis. The formation of such products was observed in reactions mediated by strong Lewis bases (e.g., PBu 3 and PhPMe 2 ) and may take place during chromatographic purification if unreacted methyl vinyl ketone is available.…”

Recent extensions of the Morita–Baylis–Hillman reaction

“…Whereas the use of PBu 3 provides a mixture of pyrroline 19 and pyrrole 20 resulting from the dehydration and desulfinylation of the tosyl group in the basic reaction medium (Scheme 21). 25 We confirmed that 19 and 20 were formed independently during the reaction because 19 cannot be transformed into 20 under these conditions. It is believed that the difference in nucleophilicity between PPh 3 and PBu 3 is the key factor for the different reaction products.…”

Synthesis of Side-Chain Functional Polyesters via Baylis–Hillman Polymerization

“…The use of these catalysts for the polymerization of 1 and 2 , however, was not found to result in polymers with molecular weights higher than those obtained via the DABCO catalyzed polymerization (see procedures 2 and 3 in Table ). Similarly, replacing DABCO by 4-(dimethylamino)pyridine (DMAP) or triphenylphosphine , also did not to result in polymers with increased molecular weights (Table , procedures 4 and 5). For procedures 3–5, Table only lists a single data point.…”

Synthesis, Molecular Structure, and Catalytic Evaluation of Centrostereogenic Ferrocenophane Phosphines

“…The reaction of N -tosylimine 8a with 2 mol equiv of the ketone in the presence of 10 mol % of chiral phosphine 2a performed at room temperature for 5 h afforded 9a in 27% yield and with 97% ee (Table , entry 1). Unfortunately, the reaction was only poorly chemoselective, affording various side products, among which the product of double addition 10 and heterocycles 11 and 12 (Scheme ) were identified by NMR analysis. The formation of such products was observed in reactions mediated by strong Lewis bases (e.g., PBu 3 and PhPMe 2 ) and may take place during chromatographic purification if unreacted methyl vinyl ketone is available.…”

Recent extensions of the Morita–Baylis–Hillman reaction

“…Whereas the use of PBu 3 provides a mixture of pyrroline 19 and pyrrole 20 resulting from the dehydration and desulfinylation of the tosyl group in the basic reaction medium (Scheme 21). 25 We confirmed that 19 and 20 were formed independently during the reaction because 19 cannot be transformed into 20 under these conditions. It is believed that the difference in nucleophilicity between PPh 3 and PBu 3 is the key factor for the different reaction products.…”

Synthesis of Side-Chain Functional Polyesters via Baylis–Hillman Polymerization

“…The use of these catalysts for the polymerization of 1 and 2 , however, was not found to result in polymers with molecular weights higher than those obtained via the DABCO catalyzed polymerization (see procedures 2 and 3 in Table ). Similarly, replacing DABCO by 4-(dimethylamino)pyridine (DMAP) or triphenylphosphine , also did not to result in polymers with increased molecular weights (Table , procedures 4 and 5). For procedures 3–5, Table only lists a single data point.…”

Synthesis, Molecular Structure, and Catalytic Evaluation of Centrostereogenic Ferrocenophane Phosphines

“…The reaction of N -tosylimine 8a with 2 mol equiv of the ketone in the presence of 10 mol % of chiral phosphine 2a performed at room temperature for 5 h afforded 9a in 27% yield and with 97% ee (Table , entry 1). Unfortunately, the reaction was only poorly chemoselective, affording various side products, among which the product of double addition 10 and heterocycles 11 and 12 (Scheme ) were identified by NMR analysis. The formation of such products was observed in reactions mediated by strong Lewis bases (e.g., PBu 3 and PhPMe 2 ) and may take place during chromatographic purification if unreacted methyl vinyl ketone is available.…”