[reaction: see text] Oxidative cyclizations of 2-(4-hydroxybutyl)furan derivatives provide spirobutenolide acetals directly; on the basis of this methodology, we describe an asymmetric synthesis of a tricyclic spirobutenolide precursor to the C(7-18) fragment common to lituarines A-C.

Sulfoximines bearing pyrazolylmethyl and aryl substituents, which are relevant to the crop protection industry, and their corresponding sulfil-A C H T U N G T R E N N U N G imine intermediates, have been prepared from sulf-A C H T U N G T R E N N U N G ide precursors by either iron-catalyzed nitrogen transfer reactions or metal-free imination procedures. Whereas the former approach leads to Nnosyl-substituted products, the latter affords Ncyano derivatives.Keywords: heterocycles; imination; iron catalysis; metal-free conditions; sulfoximines Sulfoximines have been widely used as building blocks for the synthesis of chiral ligands [1] and pseudopeptides, [2] and they are of increasing interest due to their potential as bioactive molecules. [3,4] Although a number of synthetic approaches for the preparation of sulfoximines have been described, [5] the synthesis of derivatives with heteroaryl and, in particular, arylmethyl substituents remains highly challenging. Sulf-A C H T U N G T R E N N U N G oximines containing pyrazolylmethyl groups, and Ncyano substituents (such as A and B, respectively, Figure 1) are of particular interest to the crop protection industry.[3]Herein, we report the development of two synthetic approaches towards sulfoximines with such substitution patterns.Initially, two routes were envisaged for the preparation of aryl pyrazolylmethyl sulfoximines 2 and 3 (Scheme 1): firstly, a straightforward iron-catalyzed imination of sulfoxides 1 which was recently developed within our laboratories [route A, to give 2 (X = SO 2 R)] [6][7][8] and, secondly, a metal-free approach employing an NBS-mediated sulfur imination of sulfides 4 with cyanogen amine followed by oxidation of the resulting aryl pyrazolylmethyl sulfilimines 5 [route B, to give 3 (X = CN)]. [9,10] For both approaches sulfides 4 were the key intermediates. Their synthesis began with condensation of methylhydrazine (6) with a range of b-keto esters 7a-

Aryl-1,3-diones represent a promising new class of herbicidal acetyl-CoA carboxylase (ACCase) inhibitors. The original synthesis of this structural motif employed in the research phase involved a selenium oxide mediated oxidation, the use of diazoacetate and aryl lead reagents, and a low temperature oxidation of an aryl lithium intermediate, so it was not well suited to large scale synthesis. For kilogram scale synthesis of the two aryl-1,3-dione building blocks (3 and 4), we developed an alternative route which employs a manganese or manganese−copper catalyzed alkyl Grignard coupling and a semi-pinacol rearrangement of an epoxide as the key steps. The optimized conditions could be of general interest as scalable methods for the synthesis of 2-alkyl substituted benzaldehydes and of 2-aryl-1,3-diones.

[structure: see text] Lituarines A-C are marine natural products comprising a tricyclic spiroacetal bridged at C(8) and C(18) by a functionalized ester linkage conceptually obtained from a C(19-24) alcohol and a C(1-6) carboxylic acid whose oxidation level varies at C(4) and C(5). Stereoselective routes are described to compounds 26 and 27, fully functionalized ester fragments of lituarine A and lituarines B and C, respectively.

The challenging imination of benzyl-, sterically demanding alkyl-, and heteroaryl-substituted sulfoxides has been studied. Iron(II) triflate was identified as a highly efficient and robust catalyst for sulfur imination reactions. A variety of sulfoxides and sulfides were efficiently iminated with sulfonyliminoiodinanes (PhI=NSO(2)R) at room temperature to give the corresponding sulfoximines and sulfilimines in good yields and with short reaction times.