The preparation of (Z)-2-lithio-ortho-styryllithium via an ortho-directed lithiation

Lithiation of (Z)-2-lithiostyrene with t-butyllithium/TMEDA pentane led directly to (Z)-2-lithio-ortho-styryllithium. Subsequent treatment of this dilithio compound with difunctional electrophiles allowed the preparation of a variety of benzo[b]heteroles.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30439/1/0000062.pd

Dilithiation of aromatic hydrocarbons.

The polycyclic aromatic hydrocarbons triphenylene, chrysene and phenanthrene have been dilithiated using butyllithium in N,N,N\sp\primeN\sp\prime-tetramethylethylenediamine (TMEDA) and hexane. Subsequent treatment with electrophiles allows preparation of derivatives functionalized in the bay region. In this manner reaction of 1,12-dilithiotriphenylene with iodine affords 1,12-diiodotriphenylene, for which the molecular structure was determined by X-ray crystallography. This diiodide shows gross distortion from planarity due to steric crowding of the iodine atoms. The reaction of 4,5-dilithiochrysene with sulfur dichloride gave chryseno (4,5-bcd) thiophene. This thiophene which is an isoester of benzo (a) pyrene has been subjected to biological testing and shows potentially mutagenic properties. Reaction of (Z)-2-lithiostyrene with t-butyllithium and TMEDA affords (Z)-2-lithio-ortho-lithiostyrene, a 1,4-dilithio compound. Subsequent reaction with electrophiles allows an easy preparation of indole analogs. The reaction with phenylarsenic dichloride affords benzo (a) arsole. Reaction of Naphthalene with n-butyllithium and TMEDA in hexane affords 1,8-dilithionaphthalene, which on subsequent reaction with elemental sulfur gave naphtho (1,8-cd) -1,2-dithiole. 9-Lithiophenanthrene reacts with n-butyllithium and TMEDA to afford 1,10-dilithiophenanthrene, a peri-dilithiated phenanthrene. The reaction of this dilithio compound with elemental sulfur gave phenanthro (1,10-cd) -1,2-dithiole. 1-Lithio-2-phenylnaphthalene gave bay-dilithiation in preference to peri-dilithiation indicating that 1,4-dilithiation is favored over 1,3-dilithiation. TMEDA adducts of 1,12-dilithiotriphenylele, (Z)-2-lithio-ortho-lithiostyrene and 1,4-bis(trimethylsilyl)-1,4-bis(lithio)-2,3-dimethyl-$1,3$-butadiene have been characterized by NMR spectroscopy. X-ray structure of 1,4-bis(trimethylsilyl)-1,4-bis(lithio$\cdot$TMEDA)-2,3-dimethyl-1,3-butadiene has been obtained. Each lithium atom bridges C(1) and C(4) forming a symmetrical four-membered ring, which is in accordance with the geometry of the parent compound (without TMEDA) predicted by theoretical calculations.Ph.D.ChemistryUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/103667/1/9332163.pdfDescription of 9332163.pdf : Restricted to UM users only

The reaction of sulfur with dilithio compounds. The syntheses and structures of phenanthro [1, 10-cd]-1,2-dithiole and phenanthro[4,5-cde] [1,2]dithiin

The sequential reaction of selected polycyclic aromatic hydrocarbons with butyllithium/TMEDA/hexane and sulfur allows preparation of ring-fused dithiins, dithioles, and thiophenes. In this manner, phenanthrene has been converted to phenanthro[4,5-cde][1,2]dithiin and phenanthro[1,10cd]-1,2-dithiole. Yellow crystals of the dithiin form in C2/c (#15) space group with Z = 4, a = 13.537(3) Å, b = 8.933(2) Å, c = 9.601(4) Å, and Β = 116.19 (2)°; while orange crystals of the dithiole form in P2 1 2 1 2 1 (#19) space group with Z = 4, a = 4.1507(5) Å, b = 14.436(3) Å, and c = 16.972(3) Å. Full structures have been determined for both compounds.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38566/1/520050206_ftp.pd