Cyclopentyl methyl ether (CPME) has become available in commercial quantities since November 2005 from Zeon Corporation with approval by the Toxic Substances Control Act (TSCA) and the European List of Notified Chemical Substances (ELINCS). A high boiling point (106°C) and preferable characteristics such as low formation of peroxides, relative stability under acidic and basic conditions, formation of azeotropes with water coupled with a narrow explosion range render CPME an alternative to other ethereal solvents such as tetrahydrofuran (THF), 2-methyl tetrahydrofuran (2-MeTHF), dioxane (carcinogenic), and 1,2-dimethoxyethane (DME). Conventional drying is unnecessary for general organometallic reactions including Grignard reactions, enolate formation, Claisen condensation, general reductions, and Pd-based transformations.

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Fig. 3. Structure of the phenalenium ion o f 3 . CH,CI, (X = I) viewed perpendicular to the phenalenium plane with bond lengts [pm] and angles [' I (in brackets, standard deviations in units of the last decimal given) 1111.cation was found for the phenalenium moiety, and individual polymethine units could not be identified. Remarkable, however, is the high bond order, which can be deduced from the short C(2)-C(3), C(S)-C(6), and C(8)-C(9) distances (Fig. 3).113 (X = Br), which has the same structure as the iodide with respect to the phenalenium ion, exhibits a particularly interesting lattice packing: the cations of 3 are stacked with an ecliptical arrangement of the phenalene skeletal frameworks along the c-axis, whereby the dimethylamino groups of neighboring cations are in exactly staggered positions. The interplanar distances alternate between 376 and 396 pm;Fig. 4. Structure of 3 (X = Br): view of a pair of phenalenium ions along the stacking axis (c-axis) [12].the shorter distance is apparently linked to the hexagonal network of bromide ions, which surround the pair of phenalenium ions with the shorter interplanar distance (Fig. 4).[lZ1 The recent isolation of the novel anticancer agent dynemicin A (1)l1] and the proposed cascade of reactions Engineering Research Council (SERC) for the award of a NATO fellowship. 1032 0 VCH Verlagsgesellrschaft mbH. W-6940 Weinheim. 1991 0570-0833~9ll0808-1032 $3.50+.25/0 Angew. Chem. 1n1. Ed. Engl. 30 (1991) No. 8 ( M e + H): 561.1162, found 561.1162.-24: R, = 0.63 (silica, 50% diethyl ether in benzene); 'H NMR (300 MHz, [D8]THF:D,0, 1O:l): b = 8.53 (d, J = 8.8 Hz, 1 H, aromatic), 7.45-7.10 (m, 5H, aromatic), 6.88 (d, J = 2.5 Hz, 1 H, aromatic), 6.63 (dd, J = 8.8, 2.5 Hz, 1 H, aromatic), 5.97 (d, J = 10.0 Hz, 1 H, olefinic), 5.78 (dd, J = 10.0, 1.6 Hz, 1 H. olefinic), 5.46 (br.s, l H , CHN), 2.35-1.55 (m, 6H, CH,). -30: R,=0.33 ( 5 % methanol in methylene chloride); 'HNMR (300 MHz, CDCI,): 6 =7.43 (dd, J = 5.3, 3.5 Hz, 1 H, aromatic), 7.25-7.10 (m, 4 H , aromatic), 6.56 (dd, J = 8.4, 2.2 Hz, 1 H, aromatic), 6.53 (d, J = 2.2 Hz, 1 H, aromatic), 5.58(s,lH,CHN),5.46(t,J=5.6Hz,lH,CH,NHCON),3.19-2.95(m, 2 H. CHZNHCON), 2.80 (dt, J = 11.3, 6.