A new route to diverse 2-substituted-3-methoxycarbonyl pyrroles has been developed. Diverse SES protected alpha-methylene beta-aminoesters were obtained by a 3-component aza-Baylis-Hillman reaction. Diversity arose from the aryl aldehydes which can be used in this reaction. N-Alkylation with allyl bromide under mild conditions provided the corresponding dienes. These substituted dienes were cyclized by ring closing metathesis at room temperature or under microwave-activation with Grubbs-type II catalyst to yield SES-protected pyrroline intermediates. The final pyrroles were obtained by base-promoted dehydrodesulfinylation/aromatization. The scope of each of these reactions was explored.

[reaction: see text] A new nickel-based catalytic system has been developed for phosphorus-carbon bond formation. The addition of alkyl phosphinates to alkynes is catalyzed by nickel chloride in the absence of added ligand. The reaction generally proceeds in high yields, even with internal alkynes, which were poor substrates in our previously reported palladium-catalyzed hydrophosphinylation of alkyl phosphinates. The method is useful for the preparation of H-phosphinate esters and their derivatives. The one-pot synthesis of various important organophosphorus compounds is also demonstrated. The reaction can be conducted with microwave heating.

group will be studied before presenting polymer-supported SES groups. SES−Cl in Synthesis Synthesis of Sulfonyl ChlorideThe free-radical addition 1 (Scheme 2) of sodium bisulfite on the double bond of vinyltrimethylsilane 1 catalyzed by tert-butyl perbenzoate provided the sulfonate salt 2 which is currently commercially available. This compound was directly transformed into sulfonyl chloride 3 (SES-Cl) by the action of phosphorus pentachloride, 1 thionyl chloride, 6 or sulfuryl chloride. 7 SES-Cl is a distillable liquid (bp ) 60°C/0.1 mmHg) which can be stored at room temperature. Protection of AminesThe formation of sulfonamide 4 is usually carried out at low temperatures by reaction of the amine with an excess of SES-Cl 3 in the presence of triethylamine (eq 2, Table 1). In the case of aromatic or heterocyclic amines, sodium hydride is instead used as a base.The simple and general synthesis of N-SES amino acids 25,26 should be noted: it starts from the corresponding salt using a temporary trimethylsilane protection on the carboxylic acid function, followed by reaction with SES-Cl (Scheme 3).

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The aza‐Baylis Hillman is a practical method for the preparation of α‐methylene‐β‐aminoesters. A soluble polymer supported version of this reaction has been developed. The reaction was shown to proceed in the absence of solvent under microwave activation. In the presence of 3‐hydroxyquinuclidine, the reaction time was reduced from 3–12 h under thermal conditions to 30 min under microwave irradiation. A small library of PEG‐supported aminoesters was generated.

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The Heck reaction of alkylated 2‐(trimethylsilyl)ethanesulfonyl (SES)‐protected β‐amino esters provides benzazepines in good yields. Good selectivity towards cyclisation was obtained when the reaction was performed in PEG 3400 as the solvent under microwave activation. Cleavage of the SES group with HF provides the corresponding free benzazepine. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Organo-phosphorus compounds S 0080NiCl 2 -Catalyzed Hydrophosphinylation. -NiCl 2 -catalyzed addition of alkyl phosphinates to alkynes offers a new and inexpensive method to prepare synthetically useful alkenyl phosphinates. They can be smoothly converted into other interesting derivatives such as (VIII) and (XI). Hydrophosphinylation of allene (XVII) affords the isomers (XVIII) and (XIX). -(RIBIERE, P.; BRAVO-ALTAMIRANO, K.; ANTCZAK, M. I.; HAWKINS, J. D.; MONTCHAMP*, J.-L.; J. Org. Chem. 70 (2005) 10, 4064-4072; Dep. Chem., Tex. Christian Univ., Fort Worth, TX 76129, USA; Eng.) -Jannicke 41-177