Several types of addition reactions to the C=C bond of alkyI2-cyanoacrylates, CH,=C(CN)COOR (l), are considered. The first examples deal with addition of CH-Acids (pK, less than 13) and of H$ in the presence of catalytic amounts of strong amines, also of mercaptans, thiocarboxylic, and thiophosphoric acids. P-Sulfenylchlorides and acidic phosphites add irreversibly at 20Β°C to form addition products in accordance with the distribution o f charges in 1. HCl reversibly adds to 1 and to the acid chloride CH2=C(CNICOCl (2). Alcohols and H 2 0 also add reversibly to the acid CH,=C(CN)COOH (3) and to esters of 1 to transform 1 and 3 into polymers. Triethylsilane in the presence of CF3COOH (4) reduces the C=C bond of 1 and 3 to the corresponding saturated derivatives.
The second set of examples involves reactions of 1 with P-III compounds in the presence or absence of 4. Ph3P as well as other weak nucleophiles reversibly add to 1 in the absence of 4 to cause instant polymerization. However, 4 protonates an initially formed zwitter-ion in the reaction of 1 with Ph,P,(EtO),P,(EtO),PCl,Ph,PCl and thiourea to afford stable addition products. IR spectroscopy reveals the formation of H-complexes of 4 with the CN and COOR groups of 1, which stimulates the addition of the weak nucleophile (o-C&β¬&i>PCl to the C=C bond of 1. This reagent does not react with 1 in the absence of 4. Strong nucleophiles, AkP, and (Et,N)$ in excess irreversibly add at 20Β°C to 1 to form zwitterions, which specifically react with PhN=C=O to give stable products. 1,3,2-Dioxaphosphobs react with 1 Dedicated to Prof. Shigeru Oae on the occasion of his seventy-"To whom correspondence should be addressed. fifth birthday.
either to form spirophosphoranes or 2-cyano-3-phosphoranylpropionates.