Cyclobutane ring opening of pin-2(10)-ene with mercury(II) salts. A new, high-yield synthesis of p-mentha-1,8-dien-7-ol

Abstract

The nucleophilic attack of pin-2(10)-ene–mercury(II) complex systems by water results in the opening of the four-membered ring leading to an allylic organomercury(II) derivative (11) with the p-menthane skeleton. This intermediate can be reduced by hydride to p-menth-1 (2)-en-8-ol (6a) or can undergo an in situ S_E2′ elimination yielding p-menth-1(7)-en-8-ol (9a), in high yields. (–)-2,10-Epoxypinane (15) reacts with mercury(II) salts at room temperature, giving the diol (16) in a quantitative yield. Compound (16) is a suitable intermediate for convenient preparation of p-mentha-1,8-dien-7-ol (17) and its derivatives.