The son of a Sydney nightclub owner who raped a teen in a Kings Cross alleyway and then bragged about taking her virginity has been jailed for at least three years.

Luke Andrew Lazarus, 23, said he once had "the world at his feet" and could have been a chief executive.

But on Friday he was told he would be jailed for sexually assaulting an 18-year-old woman at the back of his father's Kings Cross club Soho in May 2013.

Lazarus sat in the dock and stared after the sentence was handed down while his mother moaned in the gallery.

In sentencing him, Judge Sarah Huggett found the offence was not premeditated but said he was reckless.

"I am satisfied beyond reasonable doubt he must have realised there was a possibility she wasn't consenting," she told Sydney's District Court.

She said he was "not caring in one way or another whether she was consenting".

The court heard the victim was on her first visit to Sydney's Kings Cross on the night she was assaulted.

After entering Soho, Lazarus walked up to her, told her he was a part-owner in the venue and showed her a business card.

He then asked if she would like to enter a VIP area before taking her into an alleyway out the back of the club.

They kissed but when she said she wanted to go back to her friends he said: "No, stay."

He pulled her stockings down, ignored a second request by her to leave and said in an authoritative tone "put your f***ing hands on the wall, get on the floor and arch your back".

Scared, she complied.

During the assault that followed, the teen told him she was a virgin.

When it was over Lazarus told her to add her name to a list of conquests that he had.

"It was her right to kiss the accused and it was her right to say she wanted to return to her friend," Judge Huggett said.

"The offender ignored that."

Judge Huggett said Lazarus came from a privileged upbringing and had an inflated sense of entitlement and power when he was at the Soho.

But she found he had good prospects of rehabilitation, was unlikely to reoffend and was suffering from an adjustment disorder due to a break-up in the weeks prior to the offence.

She sentenced him to a maximum of five years in jail.

He will be eligible for release in March 2018.

Lazarus' father Andrew runs the Soho nightclub and the Eastern Hotel in Bondi Junction.

AAP