B-hexyl-9-BBN

In general, yields are low unless a B-alkyl-9-BBN is used. Thus when "B-hexyl-9-BBN is used, 1-hexyl-l-methoxycyclopropane is formed in 81% yield. 

Organoboranes participate in either ionic or radical reactions [1]. However, there are a few reports on the apphcations of organoboranes as initiators for radical reactions [2, 3]. It is reported [4] that in the presence of a catalytic amount of 9-BBN or B-hexyl-9-BBN, or to some extent B-methoxy-9-BBN, initiates the radical addition of alkanethiols to alkenes under very mild conditions to provide the corresponding dialkylsulfides almost in quantitative yields (Scheme 14.1). On the other hand, the radical reactions of alkenes with thiols are generally initiated by thermal decomposition of peroxides or azo compounds, by UV radiations, or by radiolysis [5]. The reaction initiated by 9-BBN is completely inhibited in the presence of galvinoxyl, a radical trapping agent. This confirms that 9-BBN participates in the initiation of radical addition (Table 14.1) [4]. 

The initiation is not limited to primary alkanethiols and terminal alkenes. The addition of sec- or tert-alkanethiols also affords the corresponding dialkylsulfides (Table 14.2) [4] in good yields. The reactions are found to be initiated both by 9-BBN and B-hexyl-9-BBN (Eq. 14.1). 

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