Double Elimination Protocol for Convenient Synthesis of Dihalodiphenylacetylenes: Versatile Building Blocks for Tailor‐Made Phenylene‐Ethynylenes

Abstract

Dihalodiphenylacetylenes are conveniently synthesized by a double elimination reaction of b-substituted sulfones which are readily obtained from halogen-substituted benzyl sulfone and benzaldehyde derivatives. Halogens can be incorporated at any desired positions in the diphenylacetylene skeleton simply by choosing the substitution position of the halogen on the aromatic rings of the starting compounds. The diphenylacetylenes with different halogen substituents thus obtained undergo sequential carboncarbon bond formations due to the different reactivities of the halogens. Thus, various moieties can be incorporated on the diphenylacetylene skeleton at whichever positions so that a variety of tailor-made phenylene-ethynylenes with regulated structure and composition could be designed.

Selective Cross-Coupling of Organic Halides with Allylic Acetates

“…4-iodotoluene, 4-bromobenzotrifluoride, and 3-iodotoluene were filtered through a short plug of basic alumina (1 cm) in a glass pipette before use. 4-Iodobenzaldehyde, 34 N -(4-iodophenyl)-4-methylbenzenesulfonamide, 35 2,2,2-trifluoro- N -(4-iodophenyl)acetamide, 36 tert -butyl(4-iodophenoxy)dimethylsilane, 37 4-iodo- N , N -dimethylaniline, 38 cinnamyl acetate 39 ( 2a ), ( E )-hex-2-en-1-yl acetate 37 ( 2b ), ( Z )-3-phenylallyl acetate 40 ( 2d ), ( E )-3-cyclohexylallyl acetate 41 ( 2e ), 2-methylallyl acetate 42 ( 2f ), (2 E ,4 E )-hexa-2,4-dien-1-yl acetate 13a ( 2g ), cyclohex-2-en-1-yl acetate 43 ( 2i ), ( E )-4-phenylbut-3-en-2-yl acetate 44 ( 2j ), and ( E )-3-(4-methoxyphenyl)allyl acetate 39, 45 ( 2k ), ( E )-3-(4-trifluoromethyl)phenyl)allyl acetate 46 ( 2l ), and 2-Bromocyclohex-2-en-1-one 47 ( 6 ) were synthesized according to literature procedures.…”

Expanding the Scope of Arylsulfonylacetylenes as Alkynylating Reagents and Mechanistic Insights in the Formation of Csp2Csp and Csp3Csp Bonds from Organolithiums

“…The main alkynylation methods currently used are collected in Scheme 2. The reaction of metal-acetylides with alkyl halides [7] (method a) is typically used for the creation of alkyl-Csp bonds, but it works satisfactorily only with primary alkyl halides, [8] mainly due to its competition with elimination reactions. [9] The addition of acetylides to C=O and C=N bonds [10] followed by substitution of the C-hetero-A C H T U N G T R E N N U N G atom bond by C À H (reduction) or C À C bonds on the resulting heterosubstituted propargylic derivatives, constitutes an indirect method for preparing sec-alkyl-and tert-alkyl-A C H T U N G T R E N N U N G alkynes.…”

Blue Light Emitting Polyphenylene Dendrimers with Bipolar Charge Transport Moieties

“…Compound 6 was prepared in two steps from 1-(4-bromophenyl)-2-(4-iodophenyl)ethyne (8) which in turn was made in high yield (67%) by a one-pot double elimination process [42,43]. Compound 8 was oxidized by I 2 and DMSO to give 1-(4-iodophenyl)-2-(4-bromophenyl) diketone (7) in high yield (89%).…”