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[Structure: see text] A general, highly efficient and regioselective methoxycarbonylation, by means of a palladium-salicylicborate-catalyzed protocol, of terminal alkyl and aryl olefins is described. The substrates include aliphatic alkenes, allylbenzenes, and styrene derivatives. The yields are very good (60-92%) and the regioselectivity, in favor of the linear ester, is up to quantitative--unprecedented in the case of styrenes.

Out with convention! The use of borosalicylic acid, derived from boric and salicylic acids, as the acid promoter in the methoxycarbonylation of ethylene to give methyl propionate has been investigated (see scheme). Not only was moderate catalyst activity observed, but much lower formation of phosphonium salts occurred than with conventional acids.

Unkonventionell! Die Verwendung von Borosalicylsäure, die sich aus Bor‐ und Salicylsäure ableitet, als saurer Beschleuniger der Methoxycarbonylierung von Ethen zu Methylpropionat wurde untersucht (siehe Schema). Dabei wurde nicht nur eine akzeptable Katalysatoraktivität festgestellt, sondern auch eine viel geringere Bildung von Phosphoniumsalzen als mit konventionellen Säuren.

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Carboxylic acid esters Q 0530Highly Regioselective anti-Markovnikov Palladium-Borate-Catalyzed Methoxycarbonylation Reactions: Unprecedented Results for Aryl Olefins. -The unprecedently regioselective reaction of aliphatic alkenes, allylbenzenes, and styrene derivatives affords the linear esters predominantly or exclusively [cf. (XIII)]. -(VIEIRA, T. O.; GREEN, M. J.; ALPER*, H.; Org. Lett. 8 (2006) 26, 6143-6145; Cent. Catal. Res. Innov., Univ. Ottawa, Ottawa, Ont. K1N 6N5, Can.; Eng.) -R. Steudel 16-080