Organo‐substituierte Silole durch zweifache Organoborierung von Di‐1‐alkinylsilanen

Abstract

Organo‐Substituted Siloles by Twofold Organoboration of Di‐1‐alkynylsilanes Me 2 Si(CCR) 2 [RMe ( A ), Bu ( B ), t Bu ( C ), i Pent ( D ), Ph ( E ), Me 3 Si ( F )], prepared from Me 2 SiCl 2 and MCCR (MLi, Na, K), react with Et 3 B by 1,1‐ethyloboration to form the organo‐substituted siloles Me 2 ( 1a – f ) in high yields with different reaction rates: F > B ≈︁ D > A > C > E . Me 2 Si(C C i Pent)(C  CPh) ( H ) and Et 3 B give a 5 : 1 mixture of the two regioisomeric substituted siloles 2 and 2′ . – 1a and e are deborylated with H 2 NCH 2 CH 2 OH or MeCO 2 H to 3a and e , respectively. 1a reacts with maleic anhydride to yield the [4 + 2] addition compound 4a . With (OC) 5 Fe, Cp‐Co(C 2 H 4 ) 2 , and (CDT)Ni the cycloracemic (ligand)transition metal η 4 1‐complexes [(OC) 3 Fe‐ 1a ( 5a ), (OC) 3 Fe‐ 3a ( 6a ), CpCo‐ 3a (7a) ] and the cyclodiastereomeric η 4 ,η 4 1‐complexes Ni‐( 3a ) 2 ( 8a/8a′ ) are formed. All products were characterized by multinuclear NMR, including measurements of J ( 29 Si 13 C) and J ( 13 C 13 C).